yep, that is how they work. I tend to put screws in the opposite side, though they may have changed the design since I last had one you should still have holes there. Pretty much the entire range work the same way IIRC. Been a while since i used a T-Take, though i did like them.
It seems they have changed the design, there are only single screw holes on the opposite side and these dont line up properly so Ive ditched the clips and screwed them in on the windowed side, I guess thats as secure as its going to get. Ive got to try and figure out how to attach the CD drives now since those flimsy plastic things that you stick in the screw holes have all snapped off as well.