Having the truck on a lift:

Actually no, because the back 2 plates are too heavy to lift & hold in place, you'll want a floor jack to hold them in place while you bolt them up. You can do this with the truck sitting on the ground. Other than that, it's pretty straightforward. You just need someone there to help you move the plates around, etc.

Yep, we'll be fitting the gas tank skids on our trucks pretty soon here to make sure they fit well.

Good luck and congrats!