Late model (88-98) center caps

[Texasdeere]

I have some 80's style 15x8 truck rallys for my 72. I was thinking of using the later model center caps instead of the original styled metal ones. I have seen quite a few pictures on this site of the later caps on the older wheels (5 and 6 lug) but I cant figure out how they are held on. All the pictures seem to show standard chrome lug nuts and not the threaded lugs with the plastic covers.