R.I. Gen. Laws § 11-47-43
The provisions of § 11-47-42, so far as they forbid the possession of certain instruments or weapons, shall not apply to any person who possesses or is making a collection of the weapons as curios or for educational, professional, scientific, or any other lawful purpose, without intent to use the instrument or weapon unlawfully. Nor shall the provisions of § 11-47-42, so far as they relate to the possession or carrying of any billy, apply to sheriffs, town constables, police constables, police, or other officers or guards whose duties require them to arrest or to keep and guard prisoners or property, nor to any person summoned by those officers to aid them in the discharge of their duties while actually engaged in their duties.
R.I. Gen. Laws § 11-47-43