From the end of the war until Savage took over Stevens was still owned by Westinghouse, who would have had no use for the company since the opportunity for war profiteering had vanished. What may have gone on in that year of 1919 is anybody's guess, but it must have been somewhat chaotic, what with converting all the machinery and tooling back to civilian production.** I want to think that in that interim someone commissioned that rare rollstamp, perhaps thinking of a future which never came to pass.  After 1920 it was discarded, perhaps at the behest of the new Savage management.  

Would be interesting to learn how Stevens shotguns were marked in that period.  

**I've been in the thick of it when GM and Ford powertrain plants have retooled.  It's still a case of managed chaos, and it takes as much as a year to accomplish!  

As the data fills in, I'm now pretty sure that the period from 1903 to 1915 was boom times for the 44 family.  It looks as if they built about 50,000 rifles in that 12 year span.  Compare to about 15,000 in the seven years from 1896 to 1903.