Iver Johnson was one of the larger US makers of handguns and shotguns for many years 1871-1993. Decent guns, not real high dollar, but not pot metal junk either. The design (top break) limits enegy it will handle.
OK- made it home. I THINK you have a Safety Automatic, and that date marking was used on guns made 1905-1906. Yours is likely 1905. SN is also marked on the area above the cyliner- have to remove cylinder to read it. 1905 was in the smokeless era. Unless gun has been buffed down for a refinish, should have markings on top of the barrel rib.