I read on Jim Carter's site that the back bars are Waldorf white, the 3 upright supports are black and the side pieces which meet the fenders are body color. I don't know if this info is the gospel, but if it is, it would necessitate disassembling the grille to do the painting "correct".
On my '51, the 3 inner uprights were painted Waldorf White like the back bars, not black, but the side pieces were definitely body color. Maybe the upright color varied by assembly plant. My truck was built in Oakland. I'd guess that most of Jim Carter's examples were from another plant closer to KC.
Today I picked up a rattle can of Rustoleum Canvas White, and it matched pretty dang close to the remnants of the Waldorf white at the top of one of the uprights. That's what I'm going to use.
