If adopted in accordance with N.H. Rev. Stat. § 41:14-c, in towns with 10,000 or more inhabitants, the selectmen shall have the authority to establish, and amend town ordinances and codes after they hold 2 public hearings at least 10 but not more than 21 days apart on the establishment or amendment of the ordinance or code; provided, however, upon the written petition of 50 registered voters presented to the selectmen prior to the selectmen’s vote, according to the provisions of N.H. Rev. Stat. § 39:3, the proposed establishment of or amendment to the town ordinance or code shall be inserted as an article in the warrant for the town meeting. The selectmen’s vote shall take place no sooner than 10 days nor later than 21 days after the second public hearing is held. The provisions of this section shall not apply to the establishment and amendment of a zoning ordinance, historic district ordinance, or building code under the provisions of RSA 675.