The Bonds shall be signed by the Governor and attested by the Secretary of State under the printed facsimile seal of the State and countersigned by the Treasurer by his manual signature or by his duly authorized deputy. The signatures of the Governor and the Secretary of State may be printed facsimile signatures. Interest coupons with facsimile signatures of the Governor, Secretary of State and Treasurer may be attached to the Bonds. The fact that an officer whose signature or facsimile thereof appears on a Bond or interest coupon no longer holds such office at the time the Bond or coupon is delivered shall not invalidate such Bond or interest coupon.