Is this a case of someone grinding of the reverse or something else? It doesn't appear to have been hit with a blowtorch or chemically altered from what I can see but then again I have not seen a whole lot of any of that kind of stuff, save just a few rare instances.
It is pretty smooth to the touch, like it was hit with a blank hub when it was minted.. I haven't weighed it yet to see if its significantly lighter than a normal coin made pre 82, but if it's not then do I have anything here? The subject of this post is the middle coin on the last picture that is showing the thickness of three coins side by side.
In further examination the coin while smooth has a rough or sharp feeling Edge and rim to it. At first blush I was looking at it was just my camera phone and no hand lens or digital USB it appeared as if there was some sort of residual rim or something, but in the hand is completely flat and almost totally smooth.