(a) This article shall apply to all property which is submitted to this article and shall also apply to any condominium created prior to October 1, 1975, pursuant to the "Apartment Ownership Act" if the instruments creating such condominium are amended in accordance with their terms in order to submit the condominium to this article.

(b) Existing condominiums created pursuant to the "Apartment Ownership Act" may amend the instruments creating them in certain respects in order to avail themselves of this article; provided, however, that any amendment must conform the instrument or instruments creating the condominium to this article in all necessary respects and the condominium shall thereafter be deemed to be submitted to this article. No condominium shall be established under the "Apartment Ownership Act" on or after October 1, 1975. Nothing contained in this article shall be construed to affect the validity of any provision of any instrument recorded prior to October 1, 1975.