Early 1900s Service pistol, 38 long colt or 38 special will work from what I have read. @Leadeye can likely tell us all a lot more.
I can read the serial number on the heel and cylinder they are the same, but there’s a lot of dates on the top of the barrel and kinda difficult to read.I am going to go with a Model 1902/Second Model 38 Hand Ejector M&P. Dates on top of barrel will tell you more as to which model and the serial number range.
Google that around and see if all the markings agree.
My guess is $400-$600Any idea on what it’s worth?