Mont. Code Ann. § 19-19-404

An applicant for reinstatement under the provisions of 7-32-4110 may be reinstated and added to the retired list of police officers and may enjoy all the benefits, pensions, and rights that accrue to police officers placed on the retired list in the city or town. The pension benefits to be allowed to a reinstated officer must be computed upon the basis of the officer's last full year of active service on the police force.