Mont. Code Ann. § 40-2-203

A married person's title to and ownership of the person's individual property may be proved or demonstrated in the same manner that a single person's ownership of or title to a single person's individual property may be proved. However, if a married person chooses, the person may make out and sign an inventory of the person's individual personal property, which must be acknowledged or proved in the same manner required by law for the acknowledgment or proof of a grant of real property and recorded in the office of the county clerk of the county in which the person lives.