Followup on my own wheel covers - I finally got around to removing ALL the nut covers to see what was behind them:
As can be seen, *2* of the lug nut caps reveal that they do not retain the actual cover - but the others do - this is obviously a 5-lug wheel, the duals on the rear are 10-lug, and undoubtedly follow the same general theme. SO, the other revelation here, was how to REMOVE the nut caps for further wheel/tire service - and at least in my case, the nut caps are very firmly pushed on, and not removable without some form of tool. In my case, I used a pair of channel-lock pliers with the jaws taped up to allow a good grip without marring the cover - it's a necessary thing for those caps to be firmly attached, to prevent loss, and it's undoubtedly a good thing to know how they are secured, and to include proper tools for their removal when out on the road.
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John Day....|'88 Winnebago Super Chief 27ft. Class A
Eastern .....|'88 KIT model 240 24 ft. 5er
Oregon ......|'02 Dodge/Cummins 2500 Quad Cab