AFAIK, that's the newer placement. The anchor screw was on the bottom originally, but they changed it in the early 1980s. That's new to us! I've never had trouble fitting a more recent M4 on an older bass when the holes line up, but I don't see the Schallers much these days, so perhaps some more expert opinions can chime in on this.
There are lots of people who would want the one with the anchor on the bottom for vintage repairs, so if you find any of those, be sure to share a link for those folks.