There are no studs that stick thru to the inside on a 69/70 fastback. He will need to find a trim removal tool, or make one out of some sheet metal. KD tools makes a nice one, basically a handle with a flat hook that you slide between the window and the trim. When the hook part reaches a one of the trim clips, you just pull the tool a little bit or rock it sideways and it will release the trim from the clip. I think there's about 20 of those clips. You can remove the clips also after the trim is off by pulling them straight up, but be careful as the stud it snaps over is welded to the body. To install the trim just push it down until it snaps back in place.
69 Mach One, 428 4spd, 3.91's.