those are there for accessories like bed extenders, that can rotate up and into the bed (creates storage compartment in-bed when not extending). No nutserts under these. these are just dimples that you drill through and then run self-tapping screws into.
I had a 2018 JL (Sport S) where the wheel was super toasty!
my 2022 JT (Willys) gets warm, but i definitely wouldn't call it toasty. kinda bummed about that.
based upon responses from forum members, it seems that maybe the upper threshold was changed somewhere around 2021/22...
My gut says it...