Vince old buddy.......
Getting back to your original question (and just what the hell WAS that question?.....oh yeah:) I had those same covers on a Chrysler Turbo LeBaron and stuck them back on with clear silicon caulk and they held just fine, AND you couldn't tell they were caps. So there.
If, however, you ever spring for a set of alloy lug nuts, speaking from experience here, do what George tells you and get one of those insanely expensive, plastic-lined 19mm "polished alloy lug nut sockets" to prevent marring them.
If you're too cheap to spring for a $40 socket (OK, it was from Griott's Garage - I shoulda known) AND the lugs're black, then just touch up the marrs with a Black "Magic Marker". If they're polished and you marr them, then you shoulda bought the expensive socket in the first place.
gn