Hey Capt. - the change out itself is pretty easy. Remove the single screw and the panels come off. Sometimes the fit is snug and you have to encourage the panels to let go. I never use tools for that - just work it with your fingers and it will let go. New panels go on by reversing the procedure.
Lots of places to find new grip panels. Eagle Grips is just one:
As mentioned above and I'd like to add Ajax Grips which are still being made. They have a lot of phony pearl, buffalo horn, ivory, and some solid real exotics. The same can be said for Bar S Grips, makers of the Tru-Ivory grips. They make grips for quite a few manufacturers and will custom design anything you may want or need. I turned a ROA into a 3.5" birdshead shopkeepers special so the frame was truly one of a kind. Not a problem for Bar S Grips, they made me a set of faux ivory grips in no time at all. Smithy.