If any improvement contemplated in a condominium is required by section 3210(b)(3) (relating to plats and plans) to be labeled "NEED NOT BE BUILT" on a plat or plan, or is to be located within convertible real estate, no promotional material may be displayed or delivered to prospective purchasers which describes or depicts that improvement unless the description or depiction of the improvement is conspicuously labeled or identified as "NEED NOT BE BUILT."