A manufactured (mobile) home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured (mobile) homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets and either final site grading or the pouring of concrete pads) is completed on or before December 31, 1974 or before the effective date of the community’s initial Flood Insurance Rate Map (FIRM), whichever is later.