1960 D/D Double Die Reverse Jefferson Nickel BU

Which one do you think it is?

Or perhaps Die Deterioration. This happens a lot on Nickels. They are 75% copper and 25% nickel. The nickel wears the dies down faster. When you see if uneven on the rim areas, it is probably the die wear showing. But from you images it's hard to tell. The angle of light might need to rotated 180 degrees.

The mint mark image looks like the mint mark is the normal size, but reduced with Machine Doubling in that area.

Sometimes when a doubled die is in later die states, the outside devices suffer first. I've seen some that were LDS/VLDS and the center devices would show it was a doubled die, but the outside you couldn't see it any longer.