I know this is an old thread, and don't know if you found a solution or not. But just wanted to chime in here that, those ball studs are all swaged in. So, the end will be larger than the actual hole. However, they don't just push in, you'll have to peen the end over, or swage the end of the new ones. I f they aren't really snug against the bracket, it'll become a wear point and eventually the studs might come out of the hole. The others with the threaded studs, you'll have to be mindful of what is behind, or comes close to behind the brackets. Use spacers to get the roller into the proper position from the bracket but, as I mentioned, make sure and check the clearance for the nut on the back of the bracket. I think the brackets at the rear of the windows shouldn't be much of a problem, but the bracket at the front of the windows is articulated, so make sure and check clearance through it's range of movement.
My recollection from working on mid-late 60s and early 70s Mopars back in the late 70s and early 80s was that there was a service part for those rollers. It was just the plastic roller, and they snapped onto the existing ball stud. And as I recall, yeah, it took a bit of force to get them on. My recollection was that I'd put the roller into the track, and then use a large pair of channel lock pliers to pop the ball stud into the roller. Now it's been years since I've used one, and I could be wrong. It may have not been a Mopar thing, but, the vast majority of vehicles I had then were Mopars. Can't imagine anything else. Does anyone else remember doing this???
Karl M.