The hammer is what is commonly known as the "fish hook" type sometimes found on early post-war models up to about the mid-'50s. The "lazy" ampersand in Smith & Wesson on the barrel also suggests production sometime prior to the early '70s.
How many screws does it have? Is there one in front of the trigger guard? What about at the top of the sideplate? If it has both of these screws, it is what is known as a "five screw" gun. See the photo below for reference:
My K-38 in the middle and the K-22 at the bottom are both five screw guns. The Model 29 at top is a four screw gun; the fifth screw at the top of the sideplate was deleted circa 1955 and production of this configuration continued to 1961, at which time the screw in front of the trigger guard was deleted, this creating the three-screw frame. S&W revolvers produced to this day are of the three screw type.
Also is there a model number (e.g. "Model 14") stamped on the frame under the cylinder yoke? S&W introduced model numbers in 1957 instead of using names like "K-38 Masterpiece" for each model.
The guns appears to be a 1950s vintage K-38 from this side, but the grips are of post-1968 manufacture. Those made prior to then have a diamond shape in the checkering around the screw hole.
I would estimate a value of around $550.