(a) All such refunding bonds shall be negotiable instruments and may have coupons evidencing interest, payable annually or semi-annually, and shall have all the rights of security and remedies for collection that are provided for the bonds that are refunded.
(b) They shall bear the original signature of the mayor of the city and be sealed with the seal of the city. The interest coupons may be signed with the facsimile signature of the mayor.
(c) In case the mayor whose signature appears on the bonds or interest coupons shall cease to be the mayor before delivery of the refunding bonds, the signature shall nevertheless be valid and sufficient for all purposes, the same as if he had remained in office until delivery.