I have a set of late 60’s Chrysler rallye wheel cone style center caps. 3 of them are a darker black/gray with a little bit of white speck. The other is silver and I’m trying to match up the original color to the other 3. Is the Charcoal gray wheel paint close enough to what Chrysler originally used on these center caps? Someone on another forum told me to use zinc phosphate. While it did have the specks in it, the color wasn’t even close to the original semi gloss black. If anyone can tell me what I should use, I’d appreciate it. Thanks.