(1) This act shall take effect August 6, 1975, except that the provisions of chapters 4, 5, and 8 shall take effect November 6, 1974.

    (2) The provisions of section 1020 to 1042 shall apply to persons against whom criminal proceedings are commenced on or after the effective date of those sections. Proceedings to determine the competency of persons against whom criminal proceedings are commenced before the effective date of those sections shall continue to be governed by the law in effect at the time those proceedings are commenced.

    (3) The provisions of section 1050 shall apply to persons who are found not guilty by reason of insanity on or after the effective date of that section.