There were multiple types of ski rack available, actually. (Not sure of the sources for them, though. Jeff B would probably know.) One mounted to those three holes, and also to the towing eye hole in the bumper. The skis stuck up at an angle.
Another type used the three holes you show behind the driver's head, and the other three behind the passenger's head. The skis went across the back of the roof line.
Another rack, which could be used for skis or other stuff, had tabs that stuck in the holes in the windshield frame, and the rear of the rack bolted to the holes that you show in the Targa bar.
So you are partly correct, but also partly incorrect.
--DD