It sounds to me like you are talking about a ring that presses into the back side of the hub, goes in after the seal. They are the same size around as the seal and press into the hub assembly. I noticed them when I was fixing the 3 broken wheel studs on my daily driver 86. My Troop had the rings, but the donor 86 I got hubs off of did not have them, just the seal pressed in. I put them back in on mine, but the donor rig without them seemed to be doing just fine. In fact, I had more trouble getting the seals out of it than I did on mine.

"Time and tide melts the snowman"