Before you take anything apart, take a ride height measurement from the ground to a convenient place like the wheel arch, for instance. Also count the number of exposed threads on the current bolt to give you a starting point with the new one.
The shop manual says that you can make ride height adjustments with the truck's weight on the bar. For replacement of the bolt, I think it would be better to jack it up and support on jackstands. Remove the damaged bolt, install the new one and screw it in almost as far as the old one was (judged by the thread count). Then put the truck back on the ground for the final adjustment.
Roll the truck a few feet and park it exactly where it was for the initial height measurement. Bounce the suspension to normalize it, then take another measurement. Because the new bolt is not screwed in quite as far, the truck will probably be sitting a bit lower on the side where the bolt was replaced. Now you can do the final adjustment by tightening a quarter turn until it is just right. Remember to bounce the suspension in between adjustments to normalize it.
Ford recommends that the adjuster bolt only be tightened because it loses the factory applied threadlocker when it is backed out. If it is backed out, new thread locker should be added.