Aside from putting the sideplate screws in the correct holes, a couple of cosmetic items could make yours look better. First, apply some metal polish to the nickel to shine it up, then wax it. Second, get on eBay to find some better looking grips. You should look for Magna grips to fit a square butt K-frame, similar to those on it, but there are many other styles of K-frame grips you might prefer. All should fit OK. There is really not much you can do about the plating (other than shining it up), so shoot and enjoy.
While the S-series postwar M&Ps are certainly not rare, there were numerically not that many of them made as compared to other series, fewer than 200,000 in the 1946-48 period.