RW is Remington Works and serials are not unique to models. First thing is to figure out what you have, give description w/ any writing.
Please check the link for the Manufacture Date codes details on the Remington Society of America.
Need to check the barrel date code. Remington Society of America, Manufacture date link has all the details.
You can find Remington Date of Manufacture codes at www.rimfirecentral.com in Remington Forum
It's date stamped, check the manufacture date page on the Remington Society of America for details.
1920
check the date code stamped on the barrel. Remington Society of America, Manufactured Date link has the details.
Remington Works - 1914 (late)
They have date code stamps on the barrel which can be looked up on the manufacture date link on the Remington Society of America.
1920
1943
A link to the manufacture date tables by serial can be found on the Remington Society of America on this page. http://www.remingtonsociety.com/rsa/questions/barrelcodes 1942
Since 1921 Remington has date stamped the barrel you can find the details/table on the Remington Society of America under the Manufactured Date link.