Sec. 2. (a) If before July 1, 1977, a unit established by ordinance a commission for the purpose of historic preservation, that commission may continue to operate, regardless of whether that ordinance is subsequently amended or is consistent with this chapter. If the unit wants to operate a historic preservation commission under this chapter, it must adopt an ordinance under section 4 of this chapter, and this chapter then provides the exclusive method for operation of a historic preservation agency in the unit.
(b) If a unit did not establish a commission for the purpose of historic preservation before July 1, 1977, this chapter provides the exclusive method for operation of a historic preservation agency in the unit.
(c) Subsections (a) and (b) do not limit the power of a municipality to establish a commission for the preservation of a historic street area under IC 36-7-11.3.