Manufactured in 1866, the first year of production. As found on First Models, the left side of the lower tang is stamped with the serial number. Other early production features include the "flatside" brass receiver which lacks the flare at the junction with the forearm, flat loading port cover and two screw upper tang. Henry patent marking not visible. "5" period stamped on left side of the receiver. Front sight integral to the front barrel band, two leaf rear sight, saddle ring mounted on the left side of the receiver, carbine forearm and buttstock, and trapdoor brass buttplate (cleaning rod not included).