Mont. Code Ann. § 61-9-427
Air-conditioning equipment -- sale prohibited
61-9-427 . Air-conditioning equipment -- sale prohibited. (1) Refrigerant not allowed to be used pursuant to 61-9-426 may not be sold for use in motor vehicles in Montana.
(2) Motor vehicles and special mobile equipment with air-conditioning equipment that has refrigerants not allowed in 61-9-426 , if installed prior to April 18, 2003, are not subject to any penalties provided for under Title 61, chapter 9.