O.C.G.A. § 12-3-203 (2019)

All bonds shall be signed by the chairman of the association, shall be attested by the secretary thereof, and shall bear the official seal of the association. Any coupons attached thereto shall bear the signature of the chairman of the association and may, if the resolution authorizing the issuance of the bonds so provides, be attested by the secretary of the association. Any coupon may bear the facsimile signature of such persons, and any bond may be signed, sealed, and attested on behalf of the association by such persons as at the actual time of the execution of such bonds shall be duly authorized to hold the proper office, although at the date of such bonds such persons may not have been so authorized or shall not have held such office. In case any officer whose signature shall appear on any bonds or whose facsimile signature shall appear on any coupon shall cease to be such officer before the delivery of such bonds, such signature shall nevertheless be valid and sufficient for all purposes the same as if he had remained in office until such delivery.