§ 91. Contract and oath of enlistment. Every person who enlists or re-enlists in any force of the organized militia shall sign an enlistment contract and shall take and subscribe such oath or affirmation of enlistment as may be prescribed by applicable laws of the United States and by regulations issued pursuant to this chapter. Such oath shall be taken and subscribed before any officers authorized by section seventy-three of this chapter to administer the oath of office to a commissioned officer. A person making a false oath as to any statement contained in such enlistment contract shall upon conviction be deemed guilty of perjury.