Mont. Code Ann. § 26-1-1012

If such affidavit be made in an action or special proceeding pending in a court, it may be filed with the court or clerk thereof. If not so made, it may be filed with the clerk of the county where the newspaper is printed. In either case the original affidavit or a copy thereof, certified by the judge of the court or clerk having it in custody, is prima facie evidence of the facts stated therein.