I looked at the pictures. I also looked in a GMC service manual. They are usually more complete than Chev. I still think it is the same setup as the GMC 370. It was a kind of in between size between the 2 ton and the larger trucks. The part that is on your axle stub has to be part of the bearing cone. However, if a bearing went out at some point in time and spun on the housing, someone may have pricked the housing with a center punch and drove the bearing on to keep it from spinning. I even remember bearings getting so hot that they welded themselves to the housing and I had to torch them off. Or someone may have put Loctite on the cone to keep it from spinning. I have seen some Hyatt bearings that the seal actually rode on the bearing cone. This may be one of them. Unless the rollers, and I am assuming they are barrel rollers instead of tapered rollers, are bad, I wouldn't disturb the part that is stuck to the axle housing. It could be a very difficult bearing to find.
