(a) The manufacturer shall cause a serial number to be stamped in a conveniently visible place and in a clearly legible manner on each mobile home and recreational vehicle manufactured.
(b) No units manufactured by the same manufacturer shall bear the same serial number, except that any multiple units shall contain the same serial number with letters of the alphabet designating that each is a different separate section of the same unit. Starting with "A" each such additional, succeeding section shall be in alphabetical order.