This looks like a capped die error to me, the upturned edges of the "blank" side seem legit. Hard to say without seeing it. Is it copper or zinc? It looks like a zinc to me. If zinc it would be hard for it to be post-mint as the copper coating is pretty thin. Naturally there are different types of this error depending on how long the die is "capped"
Struck Through Die Cap Lincoln Cent
Capped die nice find, its impossible to grind off the entire image of the obverse without disturbing the rim.......![]()
You're probably right, I was thinking only of a blank planchet, and knew it had to be struck on both sides together.
