I found a simple solution to mount a tailgate lightbar without removing the tailgate, and making it removable and fully adjustable. I bought round strong magnets from Home Depot and depending on the light bar I either cut the backing off the 3M tape on the bar and stuck the magnet to the exposed tape.
If the bar doesn't have the 3M tape already installed, such as the Putco Blade bar, I added the tape to the magnet and then stuck it to the bar.
I did remove the grommet from the spare tire access hole so the bar would sit flat. But to access the spare tire you can either slide the bar up or down or completely remove it.
The magnets also offset the bar a bit so it stands off the welds at both ends of bed frame.
I hope this helps those having difficulty mounting the tailgate bar.
How thick was the magnets you used?
Debagged, 20x9 Fuel Hostages +0, 295/65R20 Nitto Ridge Grapplers, Bilsteins at 2.8, weathertech mats, Tuftruck 1223's, Leer camper shell, lumber rack, DeeZee tailgate assist, a homemade platform for the floor in the back of the cab, Packrat toolbox, a UWS truck box, a bedrug tailgate rug and a bolt hitch lock.