I, finally, got out my 1902 Remington catalog (reproduction). It does notshow a chambering for .30/40 or for an all round barrel. If I understand the parts list you could buy a shotgun butt stock as an extra. Also you could have both the butt stock and the foreend checkered as an extra. I think we can date your gun after 1902. I don't know when the back position was taken out of target shooting. The catalog does not show the Remington Walker modification fo the Hepburn.