Consider each piece of clothing separately for a moment. Each one comes with a mating half in case you want to join it to another piece of clothing that happens to have either no zipper, or an incompatible one. The mating half zipper is intended to be sewn to the clothing you want to join with the zipper-equipped one.
Now, if the zippers of the two happen to mesh, then you're lucky, and you don't need either half zipper. If not, you can either do what I just described to either one of the incompatible pieces, or, if you're tall enough to take up the slack, sew the two half zippers together to make a sort of adapter.
Being the same brand, I would be very surprised if the two zippers do not mesh without needing either unattached half. Remember to hold them together with the proper orientation. If they don't mesh, I would contact Tourmaster and ask them why they don't, and what the proper fix is.