Will this bolt directly to my factory bumper frame?

Yes — designed to mount at factory attachment points on the rear bumper assembly. Torque specs and fastener type should match your vehicle's service manual.

Is the chrome finish factory-ready, or does it need prep?

Ships with factory chrome finish applied. Inspect the cap before installation; if any damage occurred in transit, the finish may require touch-up.

Can I buy just the left, or do I need both ends?

This is a single left-side cap. If you need the right-side end cap as well, order separately — they're sold individually.