Wrong calipers on 86 4KQ?

[jesse]

I bought some reman calipers from a local parts store this last week and when i compared them to the originals i noticed that there was a second threaded por in addition to the one that the brake lines screwed into.  I had the shop recheck the numbers to make sure that they had the right ones according to their system and it came back ok.  I'm a bit nervous about what these are and if they will cause any problems.  Especially since i dont ahve anything toi screw into them.  Is this where an ABS system would attach?  If so should i get different rotors?

TYIA
Jesse Erickson