The bonds shall be issued in such denomination as the legislative body may determine, except that no bonds shall be of a less denomination than one hundred dollars ($100), nor of a greater denomination than one thousand dollars ($1,000), and shall be signed by the chief executive of the municipality, or by such other officer thereof as the legislative body of the municipality shall, by resolution adopted by a two-thirds vote of all its members, authorize and designate for that purpose, and also signed by the treasurer thereof, and shall be countersigned by the clerk. The interest coupons on said bonds shall be numbered consecutively and signed by the treasurer of such municipality by his engraved or lithographed signature. In case any such officers whose signatures or countersignatures appear on the bonds or coupons shall cease to be such officer before the delivery of such bonds to the purchaser, the signature or countersignature shall nevertheless be valid and sufficient for all purposes, the same as if such officer had remained in office until the delivery of the bonds.