Montana and Gun Free Schools
Montana did something similar with respect to the Gun-Free School Zones Act, so that law is not enforceable in Montana. From the Montana Codes Annotated:
"45-8-360. Establishment of individual licensure. In consideration that the right to keep and bear arms is protected and reserved to the people in Article II, section 12, of the Montana constitution, a person who has not been convicted of a violent, felony crime and who is lawfully able to own or to possess a firearm under the Montana constitution is considered to be individually licensed and verified by the state of Montana within the meaning of the provisions regarding individual licensure and verification in the federal Gun-Free School Zones Act."
Source: Gun Laws of Montana by Gary Marbut, Montana Publishing, P.O. Box 16106, Missoula, Montana 59808. ISBN 0-9747798-0-6 Marbut's Montana Shooting Sports Association is the force behind Montana gun rights legislation and lobbying.