Fender Mounting Studs

Disclaimer First: I am definitely not a body man.
That out of the way, these are both studs that attached the lower part of the front fenders to the rocker panels (68 Dart). There are two such studs on each side of the car. First, I don't understand why they are studs instead of just a bolt...whatever. The short part of the stud uses a body bolt clip to attach to the body. Notice that the washer/nut is in a different position on these two studs. Assuming that the washer has to move in order to tighten against the fender once the stud is bottomed out, how do you move this washer?? It seems like it's in a fixed position and just rotates on the stud.
What's the problem with just eliminating the whole question and simply use a bolt instead?

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