Notwithstanding any other provision of this chapter, dealer’s license plates issued under § 46.2-1548 and temporary transport plates issued under § 46.2-1550.2 may be used on trucks or tractor trucks in the inventory of licensed motor vehicle dealers for the purpose of demonstrating trucks or tractor trucks in the inventory of a licensed dealer by a bona fide prospective purchaser. Any such demonstration vehicle may be loaded in a manner consistent with the prospective purchaser’s usual commercial activities. Such use of dealer’s license plates on demonstration trucks or tractor trucks in a prospective purchaser’s commercial activities shall be for not more than three days or 750 miles, whichever comes first, and shall not thereafter be used on the same truck or tractor truck by the same prospective purchaser for a period of sixty days. The dealer shall issue to the prospective purchaser, or to his authorized agent, a certificate on forms provided by the Department, a copy of which shall be retained by the dealer and open at all times to the inspection of the Commissioner or any of the officers or agents of the Department. The certificate shall be in the immediate possession of the person operating or authorized to operate the truck or tractor truck. The certificate shall entitle the person to operate with the dealer’s license plate or temporary transport plate for a specific period of no more than three days. This certificate shall be in lieu of any other registration, permit, and motor fuel road tax identification otherwise required by law.