Date code is stamped on the barrel, left side in front of receiver. Check Remington Society of America for the codes.
1920
Need to check the barrel date code. Remington Society of America, Manufacture date link has all the details.
Remington Works - 1914 (late)
It's date stamped, check the manufacture date page on the Remington Society of America for details.
1912
1920
1912
1920
1923
1920
1918
1919