N.J. Stat. Ann. § 3B:16-8

Every guardian of the estate of a minor or a person who is incapacitated may, and if required by the court shall, file with the surrogate of the proper county or the clerk of the Superior Court an inventory, under oath, of all the real and personal property which is in the control, possession, or knowledge of the guardian or any other person on the guardian's behalf. The court shall not require an inventory and appraisal to be filed until three months have elapsed after the grant of letters.