Partial Copper On 1943 Cent

Hi all,

To preface my post, I'm not a whacko who thinks he has found a fortune - just thought I'd share an interesting find with you, with no agenda on my part.

In a junk tray at my local coin shop I found a 1943 (Philly) cent with what appears to be about 20% copper showing on the reverse. There's not enough of it to kill the magnetism (unfortunately)! :)

I guess it's one of three possibilities:
(1) an attempted counterfeit Cu plating that recirculated;
(2) some kind of Cu-like toning of the steel alloy; or
(3) something very strange (mixed composition?)

Any opinions from the veterans out there? Even if my coin falls into the less-valuable categories (1) or (2), I am still pleased to find something so interesting in the junk tray. If you really need them, pics can be arranged. But perhaps this variety/error/damage is well-documented and you don't need pics. Just let me know...