You might try removing all oil and accumulated debris from the outside with something like mineral spirits, then following up with wax. I always hesitate to use any kind of polish unless I'm sure I really need it.
That's a great revolver you've bought there. When I saw those a few years ago I was really tempted. A dealer had them in .357, .44 Special, and .45 Colt, IIRC. I should have bought all three. I didn't. Of course now I wish I had.