Thanks for info and guidance guys. Removed the offending bolts. The holes were not threaded. New 10.9 bolts and nyloc nuts arriving soon.
Down the rabbit hole. Now plan to install new subframe bushings since only a few more bolts to drop the subframe. Will be easier to install new camber arms, and change the side diff seals and
oil (or at least loosen the drain/fill plugs).