Oh gosh no, I don't think so. If the grates on your range are rusting you probably have cast iron, is that correct? If so you can use a fine sand paper to remove the rust (or a Mr. Clean scrubbie sponge), then oil the grates OR contact your manufacturer and buy replacement grates. The only "paint" I've ever seen on a grate is a baked-on enamel surface from the manufacturer. If you (gasp) don't like cast iron you can ask if they make an enameled grate for your stove.

It turned out that the rust was actually built up grease, so I was able to just about clean the grills (there is still a few built up area of gunk that is black, so it looks good now.)

You "may" be able to use high heat paint ... the same type that is intended for the inside of the fireplace or grills(Rustoleum makes one). I'd ask about it at Lowes or HD, though.