Just looks like typical PMD to me. Took a shot. Plus, the RPMs in the 80s tend to be much closer to the primary mintmark, ruling an RPM out in this case.
Hey Top.... I think the fellows are all correct. One thing to keep in mind as well... Copper is extremely soft. I have seen some pretty astounding faux errors from perfectly placed hits on cents since being here on CT.
Darn truck drivers, when they run over a Zincoln, they should stop and bury it so paddyman has something to look for...
Appears to be zinc rot, as already mentioned above. Instead of NAV, I'd say it is LFV, or less face value. LOL