OP — I’ve learned Macintosh is usually right about shotguns.Looks like an 1893 no.3. Near as I can see the model 9 (1893 no.9) has some sort of a latch on the left side of the action I’m guessing for the removable hinge pin, and it doesnt have the rounded scallop on the sides of the action.
The buttplate monogram looks like “RA” to me (remington arms?).
Post # 6 on this thread seems to have some very good info. https://www.shotgunworld.com/threads/remington-model-9.469029/