So today at the sale, I got to talk to the lady who knew the lady who was married to the guy who owned the awesome thing, and she says that it was bought about twenty or thirty years ago while he was in Suez for the Navy, and it's over two hundred years old. (She has a really cute assistance dog, too.)
I'll buy about half of what she told me (it may have been bought somewhere in the Near East by someone who was told that it was over 200 years old) but I don't believe it could actually be that old; it's not *that* cool, and the textiles used really say 20th century to me. But this adds another level of possibility: instead of being made by an American who didn't know much about Egypt, it may have been made by an Egyptian to sell to Americans who don't know much about Egypt. Though that still leaves the question of why it was being sold, in the '70s, in a very aged condition. (If it is close to two hundred years old, it would pre-date Champollion, which would at least excuse the symbology being off and explain why there are apparently random heiroglyphs scattered around. Though I find it hard to believe it would be even as accurate as it is in that case.)
...more hearteningly, I now have an e-mail address for the actual lady it was donated by, so maybe I can get a more direct version of the story.