Howdy
I don't know why guys keep directing folks to that thread about identity and date of manufacture when there are guys here who can provide pertinent information.
This is a typical 38 Military and Police Model or 1905, 4th Change. It shipped in 1934. These are the original Service grips that it shipped with. Notice the small S&W shield on the left side of the frame, and the MADE IN USA stamp on the right side, which are typical for that era. By the way, all the hammers we are looking at here are the original long throw hammer. The OP's revolver has the same style hammer.
The front sight on the OP's revolver does not look quite right to me to be a standard half moon front sight cut down with a flat rear face. The half moon is symmetrical on these sights, here is a close up of the front sight on another 38 M&P that shipped in 1939. It may be the angle, but the front sight on the revolver in question looks like it has the flat vertical cut behind the center of the sight. I could be wrong on this, perhaps the top of the sight was reprofiled too. Notice too the small knurled end of the ejector rod which is also typical for this era.
For a while S&W was shipping their target revolvers with a front sight blade with a flat rear face that was pinned in place, as on this K-22 Outdoorsman that shipped in 1935. I do not see a pin on the front sight of the revolver in question. Notice too the aftermarket trigger shoe and grip adapter that came on this K-22 when I bought it. I have since removed them.
It is difficult to pin down the exact shipping dates of the 38 M&P 4th change because they were made from 1915 to 1942, with 758,296 made. The serial number chart in the back pages of The Standard Catalog of Smith and Wesson only says 1915-1942, 241,704-700,000. The only way to be sure when one shipped is to obtain a Factory Letter, and I understand because of the backlog there are no Factory Letters being issued at this time.
Finally, I think your offer of $300 is a bit low.
I paid $325 for a really worn old 38 M&P a few years ago. I have paid as much as $400 for a nice one. That was a few years ago, prices have probably gone up recently.
P.S. It is not a Model 10. The name change to Model 10 occurred in 1957, long after that revolver was made.
Regarding wishing it had target sights, this is a 38 Military and Police Target Model. It shipped in 1917. This is what was available in 38 Special target revolvers until the K-38 appeared in 1949. Notice the teeny little screw in the rear sight for windage adjustment. There was one screw on each side, you loosened one, than tightened the other to shove the rear sight where you wanted it, then tightened the first one again. The modern click adjustable rear sight first appeared on the relatively rare K-22 Masterpiece Prewar Model in 1940, it did not show up on a 38 until 1949.
