I don't see any damage around the area in question which leads me to believe that it is mint made. From the photo you provided I see lines and sort of a grainy texture which is consistent with a detached lamination. Any chance you could get a nice upclose picture of the area? That would alleviate any remaining doubts I have about the piece.
If you're going to purchase the piece, take in consideration that it has been polished. Otherwise it's a nice coin.
Weird how it sits right there in the breast nice and tight. That’d rule against strike through to me, which is haphazard. This almost looks like it was cut right in there. Do give us a nice crop of it when you get it. I’m thinking a lamination that peeled off. These laminations sometimes lift off on the strike.
Didn't pull the trigger. Completely forgot about it, didn't look right somehow, already sold. No big deal. Went cheap, like barely over spot. Those " cameo's" look doctored to me as well. Thanks.