Re: Trying to identify year, make and model.
Jack is correct, but I might add that numbers, if low, often are batch numbers or assembly numbers rather than serial numbers. At that time, guns made with totally interchangeable parts were not common. An assembler took the frame and fitted the parts, using a file and a lot of experience. Then the parts were numbered and the gun sent for finishing (bluing, plating, or whatever). After the finishing was done, the gun was reassembled, using the numbers to make sure the fitted parts were put back in the right gun.
This was often done in batches of 100 or so guns, so 2-3 digit numbers are also called "batch numbers."