The other posters are pointing you in the right direction. That is an early serial number for a Combat Masterpiece, and the great majority (I won't say "all," because I don't know) were blued. There are factory-nickel CMs from just a few years later, and there were nickel factory guns without adjustable sights produced in the very late 1940s. Some went to law enforcement agencies.
The odds favor your gun being refinished in nickel, but in S&W-land collectors learn early not to make blanket statements about what the company did or did not do.
Are the hammer and trigger nickeled, or do they show case coloring? If they are nickeled, that's a giveaway that the gun has had a non-factory refinish. The S&W protocol for nickel guns (even after a factory refinish) is to leave the hammer and trigger with the case-hardened colors.
Can you post a picture or two?
As a good-looking shooter (even refinished), and assuming the action and timing are sound, that's probably a $250-300 gun. If in fact it is wearing original nickel in good shape, it's a scarce variety that collectors would be interested in. You could go north of $400 for that, and maybe quite a bit north depending on how many collectors express interest.
EDITED TO ADD: And the first thing I should have said is "Welcome to the forum."