Here is an image showing a couple more of the early numbered variants of 1875 tool. Both of these tools have the smaller frame. The top one is in 44 W.C.F. and numbered 21 on the underside of the extractor plate and on the frame immediately across from that. The lower one is for 32 S.W. and has a very rare three digit number (550); again, stamped on both the underside of the extractor plate and the frame. Notice that the numbers used on 1875 tools are not unique; that is, the same number may be seen on more than one tool. This large frame tool in 50 CARB shares number "21" with the smaller frame 44 tool seen in the image below.
