I posted photos to a movie prop forum with experts on Indy props. It appears to be more authentic than I imagined, probably a 3rd generation mold of the original but from the movie production not a third party (apparently dozens were gifted to crew members). One guy said one mold in particular had the bottom edge stuck in something that obscured the tail feather detail completely and it was probably removed and the tail feather area repaired, bit then showed slightly less detail than it did originally. One of these "flawed" crew member examples went to auction for $60k! Now it was authenticated and sold by the crew member, of course, but damn. This one might be a lower generation copy, but even if it's not, it'd be hard to authenticate with no background info on its history. In any case, they seem to think I got it for a steal price at $48 shipped. It's definitely not a recent copy in any case.
That was the quick take I got anyway. To think no one even bid on it at $50 + shipping. I think the eBay photos were misleading, showing a silver cast and the seller claiming it and the staff were one piece (they're not), making it appear to be a cheap knockoff. You'd probably pay at least that much for just the staff attachment on the Relicmaker recreation version he still makes (the headpiece sells for $210 new). I have no idea what it's worth, but it's certainly better and more interesting than I expected.
This was the comparison photo I sent when I noticed it most closely matches the profiles in history auction version that has the same look to the tail feathers.