For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningEngine Compartment Fuse Block
To remove the fuse block cover, squeeze the clips and swing it up.
Notice: Spilling liquid on any electrical component on the vehicle
may damage it. Always keep the covers on any electrical component.
Engine Compartment Fuse Block
The vehicle may not be equipped with all of the fuses, relay ...
Installation Procedure
Drill 8 mm (5/16 in) for plug welding along the edges of the front
wheelhouse panel rear reinforcement as noted from the original
panel.
Drill 8 mm (5/16 in) for plug welding where front wheelhouse front panel
and front wheelhouse panel rear reinforcement overlap ...
Headlamp Replacement
Preliminary Procedure
Remove the front bumper fascia upper bracket. Refer to Front Bumper Fascia
Replacement.
Headlamp Screw (Qty: 4)
Caution: Refer to Fastener Caution in the Preface section.
Tip
Secure the headlamp fasteners in sequence, as indicated.
Tighten
2.5 N·m (22 lb in)
...