I have a few old pin tools, but if in need, could drill two holes in a piece of quarter inch plate, say 2.5 inches wide, and six inches long. push in two pins, and you got it. If in dire need, find two drill bits that fit the holes, driven ends, brace across them with a screwdriver, and turn. Many old instruments, and some machine tools use fasteners like these. I have never seen a watch back remover, I must look closer.