[69Tom]

In case you're interested, this is what JohnZ wrote over on team Camaro in response to my question regarding the original wheel painting process...

The steel wheels were received raw in rail cars, and sent through a hot cleaning and iron phosphating system, then dip-primed or flow-coated with black primer and baked. Then they they were mounted on spinning hubs on racks (5 wheels to a rack) on a conveyor and the outer face of the wheel was sprayed with body color gloss wheel enamel, and they were baked again. From there they were conveyed to the tire mounting and balancing system. Only the outer face of the wheel had body color on it.