there is a beat up Model 10 on GB now, starting at $150 with no bids yet.
I thought the Model 17 started production in 1921 due to war delay, but could be 1919. Mine is 4 digits S/N under 5,000.

I took out model 31 Christmas morning and it shoots and cycles fine, I can't wait to kill something with it. Needs a plug but I can handle that easily.