(1) Except in accordance with proper judicial order, or as otherwise provided by law, it shall be unlawful for the members of the commission, any deputy, agent, clerk, or other officer, or employee, to divulge or make known in any manner the value of any estate or any particulars set forth or disclosed in any report or return required. Nothing herein shall be construed to prohibit the publication of statistics, so classified so as to prevent the identification of particular reports or returns and the items thereof, or the inspection by the attorney general or other legal representatives of the state, of the report or return of any taxpayer who shall bring action to set aside or review the tax based thereon or against whom an action or proceeding has been instituted to recover any tax or penalty imposed by this chapter. Reports and returns shall be preserved in accordance with approved records control schedules. No records, however, may be destroyed without the approval of the director of the department of archives and history.

(2) Notwithstanding the provisions of this section, the commissioner may permit the commissioner of internal revenue of the United States or the proper officer of any state imposing an estate tax similar to that imposed by this chapter, or the authorized representative of either such officer, to inspect the estate tax returns of any individual, or may furnish to such officer or his authorized representatives an abstract of the return for estate tax of any executor or supply him with information concerning any item contained in any return, or disclosed by the report of any investigation of the return of any executor, but such permission shall be granted, or such information furnished to such officer or his representative only if the statutes of the United States or of such other state, as the case may be, grant substantially similar privileges to the proper officer of this state charged with the administration of this chapter.