In regards to, the Factory letter listing the “sold” to location and person, that is actually very common for the late production Model 1873 and 1886 serial numbers. More specifically, beginning in the year 1907, Winchester began transitioning from the old style “ledger books” to individual record cards for each serial number, and it was very common to record the shipping destination or the buyer’s information.  While conducting research for various models, I have viewed the microfilmed records cards for several hundred Model 1873 and 1886 serial numbers.  For some models the transition from ledger books to record cards did not occur until 1910/1911.  In the early 1920s, the ledger books were moved to a different location for storage, and because of that act, they were spared being destroyed in the company furnaces.  For the vast majority of models and serial numbers, the individual records cards were intentionally burned (destroyed) to provide furnace fuel during WW II and into the 1950s.

Bert