Every one I've seen has the holes, just not the brackets. Look between the monitor and the lower board under it and there should be a bracket or holes for the bracket, then up by the back door there should be 2 bolts close together or holes close together. That's where the cross brace for the top of the monitor to mount.
You are right on. That is exactly how it is.
Good
, now all you have to do is make the brackets. They are pretty basic, a little angle iron and a little time and you can have a functional set or find some on ebay.