Based on your description and the serial number, you have a .38 Military & Police Model of 1905 - 4th Change, usually simply called a .38 M&P. It was manufactured during the war years, between 1940 and 1945. This is the gun that evolved into the Model 10 in 1957 when S&W started assigning model numbers, and so it's sometimes called a "pre-10" even though, strictly speaking, it's the post-war M&Ps that are properly called pre-10s.
The drilled hole in the butt indicates that a lanyard loop was attached at one time. The crosswise hole in the same location is most likely where a small pin, called the stock pin, was fitted to help position and secure the stocks (grips).
These guns were made in large numbers, and many parts are still available. The pin and screw shouldn't be a problem (Numrich lists them); the front sight may take a bit more searching but, if you can't find one, a replacement could be made and fitted by a competent gunsmith without excessive cost. You might want to try calling S&W Customer Service and seeing what advice they might have.