When I brought my 1985 home two months ago, THREE of the four wheel covers were glued on! With 100% silicone caulk, no less....
I'm not a fan of those covers, so pitched them. Before re-painting, make sure all traces of the adhesive are gone. Then polish up those neat lug bolt heads & hit them with some clear coat.
I painted mine to match the two-tone paint job.
Brian, "in da UP"
(You may have to click on the image to make it bigger, I haven't figured out why yet!)