The Sportsman in 20-gauge was introduced in 1930, along with the 20-gauge Model 11. The 20-gauge Model 11 serial numbers began at 1000000, while The Sportsman 20-gauge serial numbers began with S1 --
In 1931, Remington Arms Co., Inc. introduced the 16-gauge Model 11 and added 12- and 16-Gauge The Sportsman to their offerings. The 16-gauge Model 11 serial numbers began at 1500000. The 16-gauge The Sportsman serial numbers began at S200000 and the 12-gauge at S500000. At some point in time, probably about when they went from the three-bird roll-stamping on The Sportsman to the one-bird they dropped the S prefix for the serial numbers. My 1936-vintage 12-gauge The Sportsman doesn't have it. During 1937-8 they dropped the separate serial number sequences for The Sportsman and moved the name The Sportsman to the breech-bolt and from then on the Model 11 and The Sportsman receivers were the same and serial numbered in the Model 11 sequence. Only real difference was which magazine tube was screwed into it. When combined Model 11 and The Sportsman 12-gauge serial numbers reached 499999 during WW-II they jumped to 700000 and continued.
The higher grade engraved guns usually had the serial number engraved in front of the loading port on the bottom and sometimes the grade was engraved there as well. During some time periods they engraved the grade on the barrel --