Can't find much on the serial number but no doubt John Knibbs will have the answer if contact him. According to his book the Model 2 started in 1908. tere was the standard model, a cadet or scout model with a longer forend. it was also available in .297/230 Morris centrefire. It looks like the rear sight you will need is the Number 8 model aperture sight or model 8A which had adjustable apertures. There are five variations of the Model 8 sight. The last serial number listed is 31720 sold in 1922. I'll keep looking about the Patent number but not come up with anything yet. Lagopus.....
