I think I might have gambled. Agreed on the pvc but acetone will remedy that often times. I see coins like this from estates at times. I buy the coin not the holder and they look legit.
And don't kick yourself after this. You erred on the side of caution. With these photos I would have done the same. The low prices for these (proofs) showed that others might have also. Everyone's money usually comes thru hard work and it would have been a shame if you did not get what you thought you might have. Other opportunities will arise and your patience will prevail eventually. And no offense intended for others who might have done differently.
The quarter for sure was a proof. Like others have said, buyer beware if its not in a legit third party holder.