(a) This chapter does not apply to a municipality any part of which is located in:
(1) a county that contains territory within the corporate limits of a principal municipality that is a part of an authority operating under Chapter 451 or 452; or
(2) a federal metropolitan statistical area or primary metropolitan statistical area that contains a principal municipality that is a part of an authority operating under Chapter 451 or 452.
(b) For the purpose of this section "principal municipality" has the meaning assigned by Section 451.001 or 452.001.