Every licensee under the provisions of this article shall be entitled to keep one or more vehicles for the purpose of collecting secondhand articles or junk in the City. The licensee at all times shall have his name in full, his street and number of his place of business and the number of his license in plain letters and figures, not less than two and one-half inches in length, painted in a conspicuous place on the side of such vehicles. If the licensee is a junk dealer, as described in Section 749.19, such fact shall be stated on the side of such vehicles. (1947 Code §16.11)