1983 P LMC Date Issue

I could be way off here, but it looks like the dies closed on a small metal button-like thing imprinting it onto the die and this is what the next coin looked like. I have something similar, but nowhere near as cool looking, where this happened with some foreign object (Mike Diamond diagnosis) and found another similar coin recently. Without any noticeable effect on the reverse if this is what happened there should be a matching struck through coin somewhere out there from the event where the die was damaged.

To me looks like something someone glued onto the coin. The mark uner the '8' looks like it was clamped down or something caused that indent there. I see a touch of contact on the top of the '3'. If this were a struck through debris, why would there be areas of the outside edge looking raised? The date area would probably be over the right roof area on the reverse:

But I don't see damage there. So I'm thinking it was added after the strike.

Mike Diamond any thoughts ?