Yours is likely a .38 Safety Hammerless, fifth model. It has 1920's-style grips, but the serial number is required for dating. The caliber would NOT be .38 Special, but rather .38 S&W, which is considerably more difficult to find. These revolvers were cataloged and sold until about 1940, but in fact most production of this model ended by the late 1920s.
It looks to be in nice un-abused condition, and I'd say you wouldn't have a lot of trouble selling it for $350-400. It actually still makes a pretty good personal defense/concealed carry weapon despite its age and the chambering in a fairly anemic cartridge (even so, the .38 S&W is just as good as a .380).