I do not know if liners were standard, I do know there's a lot of mention about mud and other debris clinging to the headlight buckets and rusting out the fenders in that area due to there not being liners. Fortunately I do not have to worry about rusting fenders though due to glass fenders that were installed and painted by a PO, I just need to keep an eye on the buckets and thought of spraying them with bedliner or something. However I also thought about going with a power antenna, and thoughts of ways to protect the unit from what you mentioned.

I am not 100% sure what to use, but I was thinking of wrapping/encasing the entire power antenna unit inside the fender in something waterproof as an option, since it's not under constant usage as a moving item that could heat up or anything (unless I am mistaken), like spray rubber or something. Any input would be cool though. I will keep an eye on this thread. :)