(a) The provisions of this part shall in no way impair the validity of any historic district previously established under any special act or the general statutes. Any and all historic districts created under the general statutes, prior to October 1, 1980, otherwise valid except that such districts, district study committees, municipalities or officers or employees thereof, failed to comply with the requirements of any general or special law, and any and all actions of such districts or historic district commission, are validated.

(b) The provisions of this part shall not apply to any property owned by a nonprofit institution of higher education, for as long as a nonprofit institution of higher education owns such property.