I'm pretty sure any grips designed for any 1911 will fit your RIA, but to be sure, take one off and take it to the gun shop--lay it over the grip of a Colt, Kimber, Taurus, etc. or a Hogue or Pachmayer grip to see that the holes match up. If so, you should be able to Google up any number or grip makers to get what you want.
As for mags, the Chip McCormick stainless mags are a good buy and reliable. The ones I recently bought came with bumper pads in the package but not installed, so it's your option whether to screw them on. I personally prefer Wilson Combat mags.
I've never seen a nickled RIA. Interesting.