67/68 gray wheels and front?

[dave6672]

I think I've seen this discussed here before, but couldn't find what I needed in a search.

I've seen 67's and 68's with the steel wheels painted either white or gray and the area around the front grille painted white, gray or body color. What dictates this? I'm looking at a 67 that has gray wheels but body color around the front grille. I realize that over the course of 50+ years may things could have been changed on a truck, but am wondering if there was some sort of package or RPO that dictated the color of the wheels and grille surround area?