Time to Paint the Steelies!

If I had to guess they were probably a semi gloss finish similar in sheen to a plain steel rim you would typically find in the trunk as a spare tire. They probably pulled steel rims off the assembly line with the semigloss black primer, and just mounted tires on them, smacked hubcaps on them. The mentality back then was they will be junk in 10 years anyways. By the time rust pops through the black primer, it will be in the hands of owner #2 or 3 who probably wont care, or will have been upgraded to mag wheels, or will have been junked. I believe the semigloss black primer was all that these were painted with. Except for cars that got the body color rims.