That where any of the federal or state agencies specified in Paragraph 3 of this act purchase bonds from any municipality as defined herein, for the purpose of enabling such municipality to purchase, improve, erect and maintain public auditoriums, whether the said bonds be issued hereunder or under the provisions of any other act, and such federal or state agency requires that the issuance and sale of such bonds shall be thereafter submitted to the people for ratification and approval, the municipality shall have and it hereby is given the power to pledge to such federal or state agency the good faith of the municipality that said municipality will submit to the vote of the people therein at the time and in the manner required by  the constitution of New Mexico the ratification and approval of the issuance and sale of such bonds by such municipality.