I also performed a simple test on the rivets. When no pressure is applied on the liner the rivets do not move. When pressure is applied, as like a head or in this case my hand, the rivets can rotate to a certain degree. The rotation is exactly from start to finish of the oxidation pattern. The one rivet could hardly move with pressure, that has the least oxidation, and so on.

I tried to get pics of everything you asked for.