Mont. Code Ann. § 15-68-506

If a sales, use, or similar tax has been levied by another state or a political subdivision of another state on property that was leased outside this state but that will be used or consumed in this state and the tax was paid by the current user, the amount of tax paid may be credited against any use tax due this state on the same property. The credit may not exceed the sales tax or use tax due this state.