All motor vehicles owned by any foreign government or by a consul or other official representative thereof, or by the United States government, or by the State or any political subdivision thereof, shall be registered as herein required by the person having the custody thereof, and the custodian shall display official registration by distinguishing marks thereon which shall be furnished by the director of finance, free of charge, and where motor vehicles are owned by the State or any of its municipal subdivisions, the motor vehicle shall bear the inscription provided for in §§ 105-6 to 105-8.