Painting them is ok and all, but i use Meguires hot shine tire coat and it has really brought back the color that used to be there. I have an 06 that was faded and i used this product. lasts for about 7 months so far and i wash my truck constantly. Not threadjacking, but its a lot easyer to spray this than to remove-prep-spray-install-chip-scratch-repete.
used it on my cowl. rear bumper step, mudguards, engine cover and bedrails.
But, to answer your ??????
If you look under the bedrails you will see the mounting tabs. Skinny flat tabs. you can either 1. get some long needle nose and squeeze them and push them out or 2. get a flat screwdriver and push on one side at a time to work them out. or 3. try to slowly work them out by pulling straight up oj the bedcap from the top of the bedside.
#1 and #2 are performed from under the bedrail.