I think I can answer the lack of dowel pin holes: The base has yet to be mated to a receiver. Once screwed on, the base was ready to be match drilled and reamed for the taper pins. Any base with reamed holes w.o finish would have already been installed. If there's full size holes that have finish or are not tapered are suspect at best. (Can't recall if any bases were done with pilot holes or not.) Makes for non-interchangable assemblies, but the practice still continues with the front sight bases on M16/M4a1s. Those are match reamed upon assembly at all sorts of weird spacings and angles.