Hi Arlen:
On original cars I've seen them painted upper body color as well as bright nickel plated. On my car both the cups and snaps were nickel plated. Hope this helps.
A400 Guy
Arlen -
The blueprint for the special snaps along the top rail clearly indicates an oxidized (black) finish. This is consistent with the original snaps on my car. From the vehicles I have seen, I believe the later (after the first 1000 or so bodies) would have the oxidized finish. Some of these were painted over. The earlier cars were probably nickel.
Doug Clayton