Putting a 318 together and something seems wrong here (see pic)

The plate had a wear mark from the cam one one side and from the bolts on the other, so I'm pretty sure it is on the right way, unless the guy who built it before put it on backwards... But it seems strange to me that there are four threaded holes with only three bolts and the tab thing just hooks into that other hole. That's really how it's designed?

The holes do line up, it was only loosely installed in this picture so it only looks like it's not aligned.