Check Remington Society of America here:
http://remingtonsociety.com/rsa/questions/barrelcodes
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
1924
1912
1912
1923
1911
1920