Licensees, under this subchapter, upon receiving a license shall be assigned a number for each vehicle to be used in said business and said licensee shall cause to appear in a conspicuous place on such vehicle said number in figures at least three inches high and one and one-half inches wide, and said licensee or his duly authorized agent operating said vehicle shall have in his possession at all times while engaged in the business of buying, selling or trading junk, the license issued to the licensee or a certified copy thereof, showing his right to engage in such business and that a number as been duly assigned to the vehicle used.
('71 Code, § 4-11-5) Penalty, see § 10.99