Mont. Code Ann. § 70-28-109

Every person made a defendant to such action by name and every unknown claimant or possible claimant upon whom service has been made by publication, in accordance with Rule 4, M.R.Civ.P., and who has not appeared in such action shall be bound by the judgment or decree entered in such action, subject to the right of any such defendants to apply for relief in any manner provided by the statutes applicable to the case of a defaulting defendant served only by publication.