After December 31, 1974, no bicycle retailer shall sell any new bicycle in this state unless such bicycle has permanently stamped or cast on its frame a serial number unique to the particular bicycle of each manufacturer. Serial numbers shall be stamped or cast in the head of the frame, either side of the seat down-post tube, or the bottom sprocket bracket. (Ord. 3451 § 1; Ord. 2670 § 1, 1996; Ord. 1641 § 1, 1975).