Just in case those aren't Compomotive wheels, my American racing 454's have a fake hub that pushes through from the rear and has a lip that holds it in the rear of the wheel. The spinners simply spin onto that as though it is a normal hub. Since it is all aluminum, it may be sticking a bit due to galling. You may need to use a hefty shot of penetrating
oil or heat to remove them if they are stuck.