49 CFR 567.6: Requirements for persons who do not alter certified vehicles or do so with readily attachable components.

A person who does not alter a motor vehicle or who alters such a vehicle only by the addition, substitution, or removal of readily attachable components such as mirrors or tires and rim assemblies, or minor finishing operations such as painting, in such a manner that the vehicle's stated weight ratings are still valid, need not affix a label to the vehicle, but shall allow a manufacturer's label that conforms to the requirements of this part to remain affixed to the vehicle. If such a person is a distributor of the motor vehicle, allowing the manufacturer's label to remain affixed to the vehicle shall satisfy the distributor's certification requirements under the Vehicle Safety Act.