Do the fog light holes line up with my factory lights, or do I need to modify anything?

The holes are pre-cut to factory spec. If your truck has OEM fog lights, they'll align. If you're running aftermarket lights, test-fit before final installation to confirm clearance.

Will this cover mount directly to my existing bumper frame?

Yes, it's designed to use factory mounting points. You won't need to drill new holes or modify the bumper frame underneath.

Should I polish or seal the chrome before installing?

The chrome comes factory-finished. You can install it as-is. If you want to maintain shine long-term, a periodic chrome polish keeps it looking fresh, but it's not required for installation.