Mont. Code Ann. § 16-3-235

Every railroad and every motor carrier transporting beer manufactured out of this state from points without this state and delivering the same to points within this state shall, if requested by the department, on or before the 15th day of each month, make an exact return to the department of the amount of such beer so transported and delivered by such railroad or motor carrier during the previous month and shall state in such return the name and address of the consignor, the name and address of the consignee, the date of delivery, and the amount delivered. A carrier shall retain for 30 months all pertinent and relevant records necessary for the preparation of this report and any other information the department may require.