There are certain patterns of selling that may reveal whether a "Northwest Coast Indian Tribal Mask" is genuine or an Indonesian fake. A beginning collector should pause before bidding and think about these facts: is it likely that a single seller would have a large and apparently endless supply of vintage, unsigned native masks? A seller may indeed have a large supply of new, signed Northwest Coast masks; these are being carved today and signed by skilled NW Native carvers; but older masks do not usually come by the dozen.
Note that newer masks should always be signed; unsigned newer masks are always fakes. Since signing has been common since the 1940's, a native item would have to be 60-70 years old, in order for one not to be astonished at the lack of signature. Yet a great many masks, unsigned, and obviously newer than that, are regularly available. If a seller has many such masks, and they are all stylistically similar, they are likely to be fakes. Real masks of that age, and all carved by the same artist, would not likely still be together in a single collection.
It is quite easy for a seller to claim that he bought a mask in the 1960's; he may say that it is genuine native carved; and this may well be true, if it were only one or two masks. But it stretches credibility to think that a seller would have bought a hundred such masks; and that they would all look oddly like the Indonesian import masks, as though the native carvers of the 1960's had been heavily influenced by Balinese carving styles: bulging eyes, gritted teeth; incorrect shapes for the eyes, brows, lips, noses, and forms; ignorance of Native proportion and grace. Check the seller's past history; some sellers have a history of selling a few such masks every week, for years. Take note of the bidders: is the mask attracting only relatively inexperienced bidders? What does this mean?
Often, these sell for only $10-$30; maybe $70; but a genuine mask, 50 years old or so, ought to be selling for $1,000 or more. Why such a low price? Because experienced collectors recognize the masks instantly as fakes, and do not bid. A beginner who cannot yet tell the difference should check out eBay's Native Americana/Reproductions category, or google for Indonesian import reproductions masks; and note the astonishing variety and pseudo-NW style of the fakes. Do not bid until you can tell real from fake at a glance.
If one has bought such a mask, note the type of wood, or show it to someone who can recognize cedar; with rare exceptions, a mask that is not cedar is not genuine NW Native art. The masks carved of streaky-grained tropical woods are not real. Note also that it is not legal to resell such masks as genuine. Even if bought as real, the Indian Arts and Crafts Act prohibits even unknowing mis-representation. Instead, such items should be returned to the seller for a refund; the IACA requires that a seller refund the price of a fake, even if he claims to be unaware it is not genuine. Failure to make such a refund is a Federal crime.
One should take note of these patterns, and bid accordingly. If it seems too good to be true......