To summarize what others have laid out much more elegantly and with detailed examples:

Grips don't cause rust, moisture causes rust.

Back in the early 1980s when I got my first Model 19 snubbie, we were convinced that S&W made the original wooden stocks on those so uncomfortable and basically unusable for most hands because they knew people would get some aftermarket grips anyway. Which we did. A set of Pachmayrs came home with the gun and the wood went into the box, never to be retrieved again.

I've had Pachmayrs, Uncle Mikes, and later CT laser overmold grips on blued revolvers for decades. If that's what works, put them on and just clean and lube underneath often enough. No rust issues.