that gun has an 'XR-3' , the original, first type of frame on it, it is not broken or really that bad off, could use a bit of 'tlc' or whatever...some folks just recoat it with something like Brownells Alumahyde , and if it wears ,scratches or nicks up later on, you strip it and recoat it again "as needed" if you are going to use the gun........
we've seen others recoat the grip frame with Krylon, or motorcycle engine paint paint, thats very durable too.......careful, do NOT let it run, better to use quick, thin coats, let it dry in between coats and you can put it in the oven at 325 degrees for around 20 minutes or so, to cure and "set" the finish ( use an old coat hanger and bend it in a 'loop' to make a stand to keep the grip frame off the ovens grates) .......do what works for YOU.......and yes, keep your eye out for another old model that may have a GREAT grip frame on it, and you can swap them out, we see LOTS of folks do that all the time, it is a COMMON Practice...............