The articles of incorporation of the corporation and amendments to the articles shall be submitted to the commissioner, and shall be subject to the commissioner's approval, which shall be endorsed on the articles or the amendments before they are filed with the secretary of state; provided, that if the articles of incorporation of the corporation have been filed with the secretary of state prior to February 27, 1945, the approval of the articles by the commissioner shall be evidenced by a separate instrument in writing filed with the secretary of state.