Does this assembly come with a bulb installed?

The assembly ships without a bulb—you'll install your own halogen or LED unit in the reflector housing. Check your owner's manual for the correct bulb type.

Will this bolt directly to my existing bracket without drilling?

Yes. This uses factory mounting points, so no drilling or brackets modifications are needed. Line it up with the existing holes and bolt down.

Do I need to prime or paint this before installation?

No prep required. Install it as-is and connect your wiring. The housing is ready to go.