There a lot of ways to restore your hubcaps. Without seeing the hubcaps, here is how I would do it.
I assume that the GMC red is the same color as Chevrolet red.
1-Shot Lettering Enamel might be a good choice. It flows out smooth. Sticks well to glass (and chrome). Wide range of colors. It dries slowly, so watch out for dust nibs. You will probably be able to wipe off any paint that ends up in the wrong place on the emblem before it dries.
1-Shot "158-L Dark Blue" seems close to the blue that the GM Heritage Ctr specified for my '54 Chev 3104 hub caps. That's the brand and color that Chevs of the 40s sells for painting emblems. You can probably buy locally for about the same price.
> Chevs of the 40s blueThe red paint for emblems that Chevs of the 40s sells is 1-Shot "104L Bright Red". You can't see the name in the photo, but the UPC code confirms the color. 1-Shot has a vermillion red paint "100-L Vermillion", but it looks too orange to me.
> Chevs of the 40s redChevs also sells 1-Shot "199-L Black".
> Chevs of the 40s black> 1-Shot web site> 1-Shot Color chartIf your hubcaps are painted, then clean, sand smooth, prime/sand/prime/sand, then paint the main color. Paint the GMC color after the main color dries ... mask and airbrush, or use a brush.
If your hubcaps are chrome, then try to smooth or strip the remaining paint without scuffing the chrome. Try some NeverDull on the chrome to minimize rust pits. Then wash clean, followed by solvent clean. Probably no need to scuff the chrome under the areas to be painted. Paint the GMC color ... mask and airbrush, or use a brush.
> Thread: Hubcaps and paint colors> Thread: Masking tape and masking film> Thread: Paint for my '54 Chevy 3104 hubcaps- Lonnie