Mont. Code Ann. § 32-1-219

A person acting in good faith reliance upon a rule, order, or declaratory statement issued by the division is not subject to any criminal, civil, or administrative liability for the action if a subsequent decision by a court of competent jurisdiction invalidates the rule, order, or declaratory statement. In the case of an order or declaratory statement that is not of general application, only the person to whom the order or declaratory statement was issued is entitled to rely upon it, unless a third person is dealing with material facts or circumstances that are substantially the same as those upon which the order or declaratory statement was based.