John T. Callahan has records for many Savage, Stevens, and Fox firearms.
He should be able to tell you not only the year your rifle was made but the date it left the factory. He provides a very nice, informative letter with production dates and other history of the firearm.
I believe the fee was $25 for the model 1920 at the time I got my letter.
As a reference, my 1920 .250-3000 s/n 71XX left the factory and was sent to the warehouse in Utica NY on Sept 11, 1920.
His address is:
John T. Callahan
Arms Historian
P.O. Box 82
Southampton, MA 01073