Correct. Considering that an adjustable sight is part of the definition on "Mountain Gun", the closest thing would be a rare revolver from the 1950s or before. Whether revolvers that meet the Mountain Gun definition were made back then and how many were made would make an interesting question for a thread in the 1896-1961 forum. There are however, a fair number of cut down 1917s around, like mine with a J frame sight and a Redfield Sour Dough blade in a shorty rifle ramp on its 4" barrel.