I just had a cleaning out a box and this was in it. The front looks normal but the back let's all copper colored. Could this be an error or just another quarter?
There is no way to really tell from the posted pics. If you can take better closeups of the coin in natural light and no flash, then maybe a determination can be made. It simply could just be an issue of toning.
Although it is hard to tell from the pics and not having the coin in hand, it sure looks like the Reverse is missing the Cladding. If so, it could have happened before or after the striking (minting) process at the Mint or possibly after it left the Mint.