(6)The registering authority shall assign to the vehicle, for display thereon, a distinguishing mark (in this Act referred to as the registration mark) consisting of one of the groups of such of those letters and followed by such letters and figures as are allotted to the State by the Central Government from time to time by notification in the Official Gazette, and displayed and shown on the motor vehicle in such form and in such manner as may be prescribed by the Central Government.[Provided that in case of a new motor vehicle, the application for the registration of which is made under the second proviso to sub-section (1), such motor vehicle shall not be delivered to the owner until such registration mark is displayed on the motor vehicle in such form and manner as may prescribed by the Central Government.]