This is a load of new 60-61 trucks. I am glad I don't worry about this kind of stuff. It would drive me crazy.

None of the color brochures from 1963 show black trucks. If no one here is absolutely sure and does not have documentation proof, that means no one on earth will know if it's right or wrong. Even a concours judge. So it may not make any difference. Very few, if any, color photos in 1963. All the 1963 brochures are artist rendered. Many times the artist got small things wrong. The brochures I see have white wheels. Some have matching color of the truck.
I have a 1963 photo at a dealership with a pretty dark 63 with lite wheels.
Gently and carefully sand the paint on the wheel. Make a wide featherd the area to expose all layers. There is no EDP in 63. Let us know what you find. I guess it could be lead base so use caution.