Do I need the left bracket too, or can I run just the right side?

You'll want both left and right brackets for balanced support. Running only one side can allow the bumper cover to shift or rattle, especially over rough roads. They're designed as a pair.

What fasteners do I need to bolt this on?

Mounting hardware is not included with the bracket. Check your OEM service manual or test-fit the bracket against your existing mounting points to confirm bolt size and quantity before ordering fasteners separately.

Does this work with aftermarket bumper covers, or only factory covers?

This bracket is designed to work with OEM geometry. Aftermarket covers vary in mounting tab location and thickness—test-fit before final installation to confirm alignment and clearance.