There are several interesting subvariants of the 1875 tool. Perhaps most obvious are the different frame sizes accommodating different lengths of cartridges. Secondly, some early examples bear a small number stamped on the frame under the extraction plate or on the under surface of the extraction plate, or sometimes in both spots. These are usually referred to as serial numbers, but some duplicates have been noted. Also, a rare tool may have a letter stamped in the same location. Third, examples with and without Berdan chisels are seen. Fourth, the base upon which the cartridge sets during bullet seating may be an integral part of the frame or may be a separate piece that is pinned in, thus allowing it to "rock" just slightly. The pinned examples have a slot milled along the long axis of the tool to accommodate the removable base. Examples bearing "serial numbers" tend to be those with the integral base.
Here is a specimen made in the days before many competing "Express" calibers forced tools to be more marked more definitively. This "1875 model" tool is one of the large frame numbers with Berdan chisel. Most of the original gold paint has worn off. The tool is marked "Winchester Express" in the usual location near the front hinge pin. This one does not have a "serial number". Note the pin on the side which anchors the base support for the seating chamber.
