The standards of quality for motor gasoline, benzine, naphtha, grease, road oil, bituminous road products, fuel oil for heating purposes and diesel fuel shall be the latest specifications adopted by the American Society for Testing and Materials or other specifications adopted as standard by an Idaho governmental agency for its use, for those products. Motor oils shall conform to the latest viscosity classifications of the Society of Automotive Engineers. Motor oils falling outside those viscosity classifications shall not carry the SAE designation.