I have a SN Colt Combat Commander, the finish was a little "yellow".
My 'smith used a wire brush and gave it a little "buff" and I was very pleased at the result.
I had inquired years ago about having it refinished to blue or park, and everyone told me to keep it stock.
I would contact Tripp Research and see what they recommend, especially if you have chips and dings, which you don't have.
IIRC, to remove the SN would entail a chemical bath which was kinda expensive and not everyone did that type of work.
Good luck and post pics if ya got 'em--before and after!!
ETA: I added a drop-in Wilson SS beavertail, McMormick rear sight, and had a new front sight staked on. Also went with black grip screws and those damned Uncle Mike's rubber grips which I need to get rid of and get some micarta (black) grips.