Stainless steel is fairly easy to work with. If you have a smooth finish, you can polish it yourself. I recommend 6 to 8 inch muslin wheels, and starting with 240 grit Polish-O-Ray, from Brownell's.
Set up and true the wheel, then add the polish and wait for it to dry. Use smooth, light pressure--let the wheel do the work. For a brushed finish, you can go up one grit finer--anything else will start giving you a very nice, shiny finish. For the satin finished surfaces, you can have the parts bead-blasted with a fine bead grade.
Or, you can cut to the chase, and send the thing back to Smith and Wesson--they do a fine job of refinishing pistols and revolvers.
Hiding in plain sight...