At that SN, it is likely to be a 15-3. It doesn't have original grips, but at that price, it doesn't matter. Even $400 wouldn't be a terrible price these days. Hogues are just fine for shooting purposes.
The only thing different in a 15-3 is a relocated rear sight screw. The Model 15 is simply a Model 14 Masterpiece (K-38) with a 4" barrel. I think those are the ultimate K-frame S&Ws in .38 Special.