The 38 Smith & Wesson Single Action, 3rd Model revolver is an interesting revolver, having been a direct descendant of the Baby Russian, which was the first 38 S&W revolver manufactured by the company. I follow dozens of auctions, use all the gun websites and hardly ever see on for sale, so if you want that one, I would say buy it since it will be a very long time before you run across another example. The nickel finish has some challenges, but would guess it would clean up quite nicely with the use of a polishing compound.
While there were over 28,000 of all configurations made, there are not many in the single-action 5 shot configuration in the US today. A few years ago, I did some research on the gun, as a result of picking up a nice 5" Target Model. It can be estimated that only about 5,000 to 7,500 were available in the revolver configuration for sale in the US. The rest were either made as 38 Mexican, 22, 32, and 38 Single Shot pistols, or were exported. You can check out a Commentary I did:
http://smith-wessonforum.com/blog.php?b=101
All 38 Single Action revolvers and single shots are classified as antiques by the BATF. SCSW4 indicates that the value of a 38 SA revolver with standard trigger guard is as follows: VG - $800, Fine (80%) - $1000, and Excellent (95%) - $1700.