The 42 dated dummies has the extra band on the case to prevent the bullet from being driven into the shell with repeated loading. The 43 cases have the 3 little triangular stamps by the primer hole (which I thought meant that it had a primer installed at one time), and you can see the wood filler through the primer hole, so I always wondered if these were reused brass.
I think the holes drilled in the cases were a post war addition. On any of these shells I have seen in the weapons tech tool boxes, the chamfered edge of the holes are not tarnished like the rest of the case.