Will this mount using the factory bolt holes on my truck?

Yes—this bracket is designed for the OEM mounting points. No drilling or modification needed. Hand tools are all you need for installation.

Do I need both left and right brackets to complete the job?

This is the left side only. You'll want the matching right bracket to ensure balanced support and proper bumper alignment across the front end.

Can I reinstall my existing bumper cover with this bracket, or does it need to be new?

This bracket works with your current cover. If your existing cover has cracks or damage, you may want to address that first—the bracket supports whatever cover you're installing.