Do I need to drill or weld this on, or does it bolt straight to the bumper?

This piece bolts to factory mounting points. No drilling, welding, or structural modification needed — basic hand tools and a socket set get the job done.

Can I paint this before I install it, or should I wait until it's mounted?

Paint it off the truck. Primer-ready finish means you can spray your color coat right away, then bolt it on once fully cured. Easier to achieve clean coverage that way.

Is this piece just the end cap, or does it include the full bumper assembly?

This is the end cap only — the right-side bracket that closes out the bumper profile. You'll need the center section and matching left cap to complete a full rear bumper.