Do I need any fasteners or hardware to install this bracket?

Fastener specs aren't confirmed in the product data. Bring your old bracket and hardware to the install—use what came off as your guide, or check your vehicle's service manual for torque specs.

Will this work if I'm replacing just the bumper cover, or do I need both brackets?

This is the right-side bracket only. If you're swapping the entire rear bumper cover, you'll need both left and right brackets for proper support. A single bracket will leave one side unsupported.

Should I paint this bracket before installation?

The bracket stays hidden behind the bumper cover, so paint is optional. If it will be visible during install or you want rust prevention, light prep and spray will work fine—it's not a cosmetic part.