Yessir, I did, and it matches what I learned when I shopped for Ceiling Fans a few years ago. Asked about Ball Bearings and was told the fans used Sleeve Bearings because BB's were noisy. The may start out quiet, but they get louder with age. A new Alternator is quiet when you spin it over. One that has some miles on it sounds like a roller skate wheel. I think I'll either clean or replace the sleeve bearings. They look like "spherical" bearings that are meant to align themselves to the shaft.
The writeup doesn't talk about my question about riveted motor, and I notice a new nut in a photo, holding the motor together. He refers to replacing the rivets in the bearing retainers with screws and nuts, but not the motor assembly rivets/screws. And they aren't on his materials list. I'm not too worried about that. If they ARE rivets, I can only hope to find screws long enough.
More on that as I pursue that little overhaul. Those sleeve bearings have run since 2002, probably with no maintenance, and they still aren't loose.