N.J. Stat. Ann. § 40:20-19

Any county that shall have heretofore adopted the provisions of an act entitled "An act to reorganize the government of counties of the first class in this state," approved March twenty-sixth, one thousand nine hundred and twelve, and is now governed thereby shall hereafter be governed by the provisions of sections 40:20-2 to 40:20-18 of this title and the members of its board of chosen freeholders shall be elected as therein provided. Nothing herein contained shall require a reorganization of such board.