Someone must know the answer:
Here is the rebarreled, reproofed Reilly SN "1833" w/o Scott gas check - with the weight, barrel length, pistol grip stock it is almost certainly repurposed from a big bore rifle:
It looks very similar to this gun SN 35554 (1907):
I'm thinking there is one of three possibilities for "1833":
-- It was made before Feb 1882 (very unlikely)
-- Big bore rifles did not use the gas check patent, (another indication that "1833" was originally a rifle.)
-- Or there's been major work in the action (no indication of this).
So someone must know if the Scott Gas Check Patent was used on rifles.