The 3E is a pretty typical pre-13 gun likely right around 1900. It has the two piece top tang, bushed firing pins, regularweight frame, and 3 position safety I would call standard on the pre-1913 L.C. Smith.
Nitro Fluid Steel barrels standard for the grade with very yellowed twin ivory beads. It does not have the round stop check I assume you are asking about, and I would ask the experts- is that check seen on ejector guns ?