At my coin club meeting a couple of months ago I bought a small penny hoard of mainly uncirculated wheat cents and found a couple of nice error cents. Best treasure I have ever found. So to all my other fellow treasure hunters I say keep looking there still nice coins to be discovered.
I think the 12-D is PMD. If it were legitimately a mint error, the fields between the rim and the bottoms of the wheat stalks would be recessed below the rim, and darker from less wear than the higher areas. They are not, which tells me the depression on the obverse pushed material through to the reverse in a post mint incident.
At first I figured the 12 D to be PMD but then I reasoned that something striking the cent hard enough to leave a depression almost all the way through would have obliterated the O in GOD and the E in WE. I also figured a force that hard would have made the cent irregular in shape. Thus I concluded that it would have had to occur when still in the coining chamber and being retained by the collars when the hammer came down on something very hard (perhaps a piece of the die fell out). I will say my reasoning could be flawed as I have not seen many coins like this. Thanks for taking time to help me reach the proper conclusion.