I put the smaller '88 and up 4X4 center caps on mine. They attach with screws from the back, but I drilled through the cap and attached them from the front with stainless steel screws. I took the plastic nut covers from the newer model and set them over my stock (little) lug nuts and set the center caps over them to pinch them against the wheel and then tightened down the stainless screw. I think they look better with the smaller cap,
Scott