Ethan,
I believe one test to see if there is clearcoat left is to go back with a small amount of rubbing compound and polish a small area of the wheel with a white cloth. If you see silver residue on the cloth, it means you've hit paint. If not, you probably still have some clearcoat left.

Maybe they spray a heavier clearcoat on the wheels than on the body?

__________________
Steve
'93 400E