A wholesale dealer in liquors may continue to use records of receipt and disposition in a format previously prescribed or approved. Those records must show the information required by paragraph (a) of § 31.155 or paragraph (a) of § 31.156, as applicable. The records must be preprinted with the name and address of the wholesale dealer. Each sheet or page must bear a preprinted serial number, or page serial numbers may be affixed in unbroken sequence during the preparation or processing of the records. A serial number must not be duplicated within a period of 6 months.