Since it's a bone fishhook, we just need to figure out when the bonefish went extinct. A flint fishhook, as you noted, would be fake, because the flintfish isn't in the Americas. ;')
[note: I'm not a fisherman, so if their are bonefish and flintfish, I wouldn't know]
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Thanks, Liberty Valance, for the "how to" on making a deer bone fishhook!
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Here's an interesting page on making a fishhook from antler, which is stronger (in tension) than bone -- and certainly stronger (in tension) than any knappable stone.
As a reasonably-competent flintknapper and lithic technologist, I'm sure I could make a 'flint' "fishhook" as nice as those for sale on e-bay. All it would take is a big flake of knappable stone, a deer "cannon bone" punch -- and a lot of patience and luck...
OTOH, (as a fisherman) I doubt I would make the effort because:
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BTW, for those of you who are interested in such things the "Primitive Ways" website has lots of other neat "How to" stuff, as well...