These are only "position" holes in the B and C pillars. The B pillar only has the slots and must have the hinges from a donar car welded/brazed in. The latch position on the Notch has the 3 holes but no nuts in place. A plate with the nuts must be added. The Square has self tappers in the C pillar for the latch attachment so the hole positions may or may not be marked which makes that one a bit easier.
There have been past posts on here showing how to go about fitting the popouts to Australian built Notches, none of which were fitted with the popouts but all the slots/holes are there as you have found. As you have mentioned 2 c'sink screws holding the hinge (do you mean latch??), I presume that you have a Square.
See this post for more info:
http://forums.aussieveedubbers.com/viewtopic.php?tid=60859#pid579020
DH