The Socialite Auctions reference guide to Hermés date codes by Year:
Hermés collectors often begin their authenticity checklist for handbags by first determining the year of the handbag. Each Hermés handbag has a blind stamp with a letter that signifies the year of production. Handbags prior to 1970 are stamped with a letter only. Handbags after 1970 are stamped with a letter inside a shape. This guide will serve as a quick way to determine the year of the handbag which is only the first step in determining the authenticity of an Hermés handbag.