Will this bracket work with an aftermarket bumper?

This bracket is designed for factory Silverado bumpers. If you're running an aftermarket bumper, check that bracket's mounting pattern—compatibility isn't guaranteed across different manufacturers.

Do I need both left and right brackets?

Depends on your damage. If only the left side is cracked or bent, one bracket is enough. If both sides are compromised, order the right-hand bracket separately.

What prep is needed before install?

Remove the damaged bracket and clean the mounting points. If you're painting this to match your bumper, do that before installation. Once it's dry, bolt it to the factory attachment points using your vehicle's service manual torque specs.