Having rebuilt a couple of original matching number 2 Speeders my observations are that the serial number of the gear is stamped on the top face of the flange of the hub. This number is repeated on the plate on the low speed gear that holds the sprocket to the drum. Often low gear drum and sprocket assemblies were swapped when owners experimented with different low gear ratios so the numbers may not match.
Scotts issued 2 speed gears to the assembly line in the same sort of semi random way that frames were issued. ie not in strict numerical order but within a range. The serial numbers are recorded in the Sales Ledgers. I can tell you that 6544 is May 1926, 7721 Aug 1928 and 8298 Dec 1929. In 1919 they were in the range 5-600’s so I would estimate 3765 is in the early 1920’s.
I do not know if gears that were overhauled by the factory had a repair number stamped on them but I rather suspect that few gears would have been overhauled by them rather than a local dealer.
