Mont. Code Ann. § 72-1-107

72-1-107 . Effective date -- applicability. (1) This code takes effect on July 1, 1975.

(2) Except as provided elsewhere in this code, on July 1, 1975:

(a) the code applies to any wills of decedents dying thereafter;

(b) the code applies to any proceedings in court then pending or thereafter commenced regardless of the time of the death of decedent, except to the extent that in the opinion of the court the former procedure should be made applicable in a particular case in the interest of justice or because of infeasibility of application of the procedure of this code;

(c) every personal representative, including a person administering an estate of a minor or incompetent holding an appointment on that date, continues to hold the appointment but has only the powers conferred by this code and is subject to the duties imposed with respect to any act occurring or done thereafter;

(d) an act done before July 1, 1975, in any proceeding and any accrued right are not impaired by this code. If a right is acquired, extinguished, or barred upon the expiration of a prescribed period of time which has commenced to run by the provisions of any statute before July 1, 1975, the provisions shall remain in force with respect to that right.

(e) any rule of construction or presumption provided in this code applies to instruments executed and multiple-party accounts opened before July 1, 1975, unless there is a clear indication of a contrary intent.