AFAIK, there is no direct/online SN/DOM reference for all Stevens firearms.
The reason is that, just after the end of WWI, when Stevens Arms & Tool was hauled before the US Congress to answer accusations of war profiteering, the corporation told Congress that all their production records just happened to have recently been "lost" in a small fire in the records room at the factory, and so could produce no records.
That holds true to this day, even after Stevens was acquired by Savage Arms - however, in 1949, Savage started marking most of their firearms (all brands) with a date/letter code within a circle, stamped into the lower part of the receiver(s), starting with an "A", up until 1970.
Savage skipped some letters, due to their similarity to numerals - the exact codes are available in the FAQ at
www.savage24.com
For arms outside that timeframe, one must rely on the amassed data of knowledgeable, long-time collectors & ex-employees - often published in various books, etc
.