There is often confusion between USPS posters, Unofficial Souvenir Pages, and Official Souvenir Pages. The purpose of this guide is to help collectors (and stamp dealers) understand the differences.
In the late 1950's the USPS noticed the increased interest in collection First Day Covers and felt it was necessary to establish a standard procedure for processing such orders. They also wanted to encourage this type of collecting. With this in mind they began issuing Stamp Posters, sometimes called Bulletins, with instructions on how to create covers.
Stamp Posters were printed to be displayed on Post Office bulletin boards starting with the 49-Star Flag stamp (7/4/59) and continued thru Rachel Carson stamp (5/28/81), and were also made available to collectors. They are 8 x 10-1/2 inches, and were printed on lesser quality paper without watermarks. At first the posters were printed in gray but soon the USPS began to print them in a single color similar to the color of the stamp. Printed by the Government Printing Office, they were available in mint condition (un-cancelled, with no stamps affixed, folded in thirds). Stamp Posters were issued for every US postal issue, including stamped envelopes, postal cards and aerogrammes. They included an image of the stamp(s) along with information about the stamp and it's subject. At some point the USPS began sending posters out unfolded in large envelopes. Early unfolded posters are rare and command a premium.
Unofficial Souvenir Pages: Early on enterprising collectors and dealers began affixing stamps to the posters and having them first day cancelled. Since they often affixed their own stamps, many possibilities exist including plate blocks, zip blocks, tab singles, coil line pairs, and combinations with other stamps. Unofficial Souvenir Pages were created for most US postal issues, including stamped envelopes, postal cards and aerogrammes. They were created on both folded and unfolded posters. Like Stamp Posters unfolded examples command a premium.
Official Souvenir Pages: By about 1970 the USPS noticed the growing number of Unofficial Souvenir Pages being created and planned to take advantage of their popularity. The first Official Souvenir Page was the Family Planning issue of March 18, 1972. Like Stamp Posters there are 8 x 10-1/2 inches but are printed on high quality tinted bond paper, often with watermarks and, for the first time, the USPS affixed the stamps and added the first day cancellation. Beginning in 1988, page numbers were printed in the lower right corner. They consist of four digits; the two-year digit followed by the sequence on issue number, e.g. 96-01, 96-02 etc. Pages issued prior to 1988 were not printed with a number, but have since been assigned a number in The Postal Service Guide to US Stamps by the USPS/ASPPP going back to 1972, the start of the subscription program. Since the family Planning official page was only available at two locations in New York City and was not mailed to subscribers it is given the designation 72-00. The USPS has mailed Official Souvenir Pages to subscribers since the Yellowstone Park issue of 1972 that has been given the designation of 72-01. Official pages have been issued (with only a few exceptions in 2000) for every US stamp. When a full sheet of stamps was affixed the information was printed on the back, which is white. Unfortunately the USPS did not issue Official Souvenir Pages for postal stationary such as stamped envelopes, postal cards and aerogrammes.
Overlapping dates: As you can see both Official Souvenir Pages and Stamp Posters were issued between March 1972 and May 1981. There are both official and unofficial pages for the Family Planning stamp and others probably exist. The best determinate between the two is the quality of the paper.
Postal Stationary Pages: As noted above, Official Souvenir Pages where not issued for postal stationary so collectors who wanted complete collections created them from Stamp Posters during the overlap period. These are referred to as Unofficial Souvenir Pages since individuals created them. Most Postal Stationary Pages were created by sending the stationary item to be first day cancelled and then attaching it to the Stamp Poster with glue or corner mounts (the preferred method). However some collectors attached the stationary item to the poster first and sent the entire page to be cancelled. The latter will have the stationary tied to the poster by the cancellation while the former will not. Postal Stationary Pages that are tied will command a premium over pages that are not.
American Commemorative Cancellations: Official Souvenir Pages were slightly redesigned and renamed American Commemorative Cancellations in 2002. The image of the stamp was removed; the page number was reduced in size and located in parenthesis after the USPS copyright; and the bond paper is not watermarked. When a full sheet of stamps is affixed to the front the text information will be on the reverse, which is tinted to match the front.
Scott Catalog Information: The values listed in Scott Catalogs are for Unofficial Souvenir Pages followed by Official Souvenir Pages and American Commemorative Cancellations. They DO NOT list values for any Stamp Posters (without stamps and FDC) or Unofficial Souvenir Pages after the March 1972 Family Planning issue. This seems to be a source of confusion as to the value of some items when inexperienced people assume that Stamp Posters and Unofficial or Official Souvenir Pages are the same. It should be noted that Scott values for Unofficial Souvenir Pages are for folded examples and that unfolded examples command a 50% to 100% premium.
Condition: As with any postal collectable condition is an important consideration. As mentioned previously, unfolded Stamp Posters and Unofficial Souvenir Pages command a premium, but not if they are seriously damaged. Minor damage such as wrinkles (not Creases) or corner dings does not seriously decrease the value of a page, especially early ones. Unfortunately 3-hole punches, tears, and water of other stains render the page nearly worthless, except for the rarest of pages. Indentations from improper storage in 3-ring binders also affect the value, depending on severity, and should always be noted when selling such items. One or two tack holes at the top of Stamp Posters is acceptable (after all they were meant to be displayed on bulletin boards), but must be noted when selling. Multiple tack holes or ones in the stamp's image are generally not acceptable. Holes of any kind in Unofficial Souvenir Pages, Official Souvenir Pages or American Commemorative Cancellations are totally unacceptable.