An automobile repair facility shall offer at the time the repair work is authorized to return to the customer any parts which are removed from the motor vehicle and replaced during the process of repair; provided that any part which is required to be returned to a manufacturer or distributor under a warranty agreement, trade-in agreement or core charge agreement for a reconditioned part need not be returned to the customer. If the customer wishes the return of replaced parts subject to core charge or other trade-in agreements, customer agrees to pay the facility the additional core charge or other trade-in fee. The customer retains the right to inspect requested returned parts even if custody is refused.