Since it has the one line "MADE IN USA" stamping, it was built sometime from mid 1922 onward.
The stamping looks like it was done by hand. Also, my commercial 1917 in the 180xxx range is stamped with the barrel pointing to the right and the font is smaller.
Go to this thread and look at the SN photo in post # 7:
Stamp or Mark on 1917
This is how my 1917 is stamped, with the small digits.