The powers and duties of guardians and the rights and privileges of wards under guardianships established before July 1, 1990, are as provided by this chapter as it existed on June 30, 1990, and are not affected by chapter 405 of the 1989 Session Laws, except that guardians appointed before July 1, 1990, must comply with the requirements of subsections 2, 4, 5, and 8 of section 30.1-28-12.