The bonds and notes of the authority shall be executed by the manual or facsimile signature of either its president or its treasurer, as shall be provided in the resolution under which such securities shall be issued, and the seal of the authority or a facsimile thereof shall be affixed to any bonds so issued and attested by its secretary; provided, that if bonds are executed entirely by facsimile, such bonds shall be authenticated by the manual signature of the bond trustee, registrar or paying agent. If, after any of the bonds shall be so signed, whether manually or by facsimile, any such officer shall for any reason vacate his said office, the bonds so signed may nevertheless be delivered at any time thereafter as the act and deed of the authority.