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 WarningDriver or Passenger Seat Retractor Side Belt Replacement
Warning: Refer to SIR Warning in the Preface section.
Warning: In order to prevent accidental deployment and the risk of personal
injury, do not dispose of an undeployed inflatable
restraint seat belt pretensioner as normal shop waste. Undeployed seat belt
pretensioners contain substance ...
Installation Procedure
Clean and prepare the attaching surfaces for welding.
Apply one-part windshield urethane adhesive as noted from the original
panel.
Position the roof panel (1) on the
vehicle.
Verify the fit of the panel.
Clamp the panel into position.
Spot weld accor ...
Older Children
Older children who have outgrown booster seats should wear the vehicle safety
belts.
The manufacturer instructions that come with the booster seat state the weight
and height limitations for that booster. Use a booster seat with a lap-shoulder
belt until the child passes the fit test below: ...