These guys are feeding you the good stuff Ed. If you look at the rear hub cross section the bearings are inside the upright behind the drive flange. The knockoff is just a tube off the flange. The caps don't cover anything and if it ain't needed on a race car.......
The front caps are required to keep the dust from the outside. The irony is they don't have seals on the inside and the bearings would fill with water and rust if you were caught in the rain.
