I was wondering If this 1996 P Quarter had any value. I'm not certain whether to consider it double stamped, but it does have the impression of the opposite side on each side. Sorry for the bad photo quality.
I will try to get a friend to snap some better photo's of it. It's hard to explain but the double stamped portion is more clearly visible in darker light. Also, to clarify, since the pictures aren't very good, it seems to have been stamped with the opposite side on both sides. (Eagle on the front Washington face, and Washington face on the back of the Eagle side) The wings of the eagle are somewhat visible near the photo of the front of the Washington side.
I wouldn't be so sure it is post mint damage, I am having a hard time seeing how post mint damage could do this. It may be a flip over double struck, I would have it looked at in person by a reputable coin dealer.
I had a friend take a couple photo's for me. I'm not sure how much better they are. It's hard to explain but the overlay seems to be more visible in darker light. I don't see how this could be from post mint damage as the overlay seems to be behind the inscription, or from within the coin. But I am by no means an expert.