Funny because I'm going through this right now with my old MGB wire wheels that are painted silver. I had them media blasted and primed them, now comes the silver paint. Moss, (the Pelican of British parts), sells a spray can for way too much $$ that is supposedly the correct silver. I don't care about being 100% correct on the color, just somewhat close and a color I like the best.
I experimented with a couple of silvers I had in my spray can collection yesterday, one was a Rustoleum called "Aluminum" which is a beautiful silver but way too light and shiny, looks basically like chrome, (or fresh raw aluminum). The other was Duplicolor which I think is right on the money. I've used it before on rims with clear coat over it but the old MG wires did not have clear coating, it just doesn't look right.
Here are some photos of the one painted with DC and a picture of the can, this is no clear coat. The white ones under it are in primer:
