Does this mount at factory points or will I need to drill?

Mounts at factory attachment points — no drilling. Just unbolt the old cover and bolt this one in place using your truck's existing hardware.

Will this fit if I have a trailer hitch installed?

Depends on your hitch receiver style and how far it extends. Verify clearance between your hitch and the new cover before securing — you may need to temporarily remove the hitch or adjust bracket spacing if they're too close.

What prep work is needed before painting?

Wash it down and inspect for any shipping damage. If you're spraying, standard panel prep applies — sand and prime per your chosen paint system. No special surface treatment is required before basecoat.