This Part does not apply to the following persons and things:
(1) Sheriffs or equivalent municipal officers in municipalities of over ten thousand, when they are acting in their official capacity.
(2) The arms, accoutrements, and equipment of the military and naval forces of the United States or of other officers of the United States authorized by law to possess weapons of any kind.
(3) The arms, accoutrements, and equipment of the militia.
(4) Any firearm which is unserviceable and which is transferred as a curiosity or ornament.