Don't quote me on this, it's just what I remember from 50 years ago working in a Chevy garage. I believe they were a dull allmost flat black not at all gloss black. The running board is simply a step and there was no need to have a fancy finish on it that would just get scratched up.
One of the boys over at VCCA will probably have some documetation on it.
Denny Graham
Sandwich, IL
