mikelj:
The term, "Pre Model 10" is one thought up by collectors, not the Smith & Wesson company. It is suppose to describe those .38 Military & Police revolvers made between 1945 when production was resumed after World War Two, and 1957 when model names (such as "Military & Police" or the short form "M&P") were changed to numbers (model 10, in this case) because names were causing problems with the manufacturer's early day computers.
Your Military & Police .38 revolver, serial No. (whatever, not posted) would be classified as a .38, 1905 Hand Ejector.