Mont. Code Ann. § 15-16-504

On trial, a certified copy of the assessment signed by the county clerk and recorder of the county where the assessment was made, with the affidavit of the county treasurer that the tax has not been paid attached to the copy, describing the assessment as on the property tax record or delinquent list, is prima facie evidence that the taxes, plus interest, penalties, and costs, are due and entitles the county to judgment unless the defendant proves that the tax was paid.