(1) When a death occurring in this State has not been registered, a certificate may be filed in accordance with the regulations of the Department.(2) A certificate of death registered more than one year after the date of death shall be marked "delayed" and shall show on its face the date of registration.(3) No certificate of death registered pursuant to Section 15.1 of this Act shall be marked "delayed", nor shall any such certificate be identified in any other way as having been registered other than pursuant to Section 18 of this Act.