Compiled Laws, Chapter 750. Michigan Penal Code § 750.231b

Sec. 231b. Sections 223 and 228  1 do not apply to a duly authorized police or correctional agency of the United States or of the state or any subdivision thereof, nor to the army, air force, navy or marine corps of the United States, nor to organizations authorized by law to purchase or receive weapons from the United States or from this state, nor to the national guard, armed forces reserves or other duly authorized military organizations, nor to a member of such agencies or organizations for weapons used by him for the purposes of such agencies or organizations, nor to a person holding a license to carry a pistol concealed upon his person issued by another state, nor to the regular and ordinary transportation of pistols as merchandise by an authorized agent of a person licensed to manufacture firearms.