[Richard]

Hard to say.

The sealant may be holding the rivet head in place. Try to pull one of them out.

If you look at the right hand side of the second pic, you can see the upper skin shifted to the rear, and someone at some time simply filed it away to line up with the lower skin.

And I agree, if a repair was done, it was without jacking up the coach and realigning the skins.