SInce you have so little in it, I would not change the caliber. If it’s mechanics are as good as you think, I would send it in to S&W and get it re nickeled. If I had a nicer pair of grips or maybe even Target grips I would change them out. If not I would strip the ones on it and use some tuna oil. Then I would keep it. You would have a very nice gun that looks great and functions perfectly for years to come.