Going from memory here, but the S Prefix was used from 1946 until about 1948 when S&W switched to the C prefix and 4 line address. Your gun is actually called an M&P, the revolver which became the Model 10 in 1957 when S&W switched from model names to model numbers. Depending upon condition of the gun and the grips it could be worth anywhere from $150 in poor but shootable condition, and going up to two or three times that depending on better condition and other factors.
Almost forgot, welcome to THR. A couple years ago my inquiry about a very similar S&W M&P brought me here. I hope you enjoy the forum.