Mass. Gen. Laws ch. 90, § 33A

In case the registrar, deputy registrar or the duly authorized agent of either whose signature or a facsimile of whose signature appears on a certificate of registration, a license to operate motor vehicles, any other certificate, or license, or any notice, issued under the provisions of any statute, or rule and regulation relating to motor vehicles, shall cease to be such registrar, deputy registrar or agent prior to the effective date thereof, such signature or facsimile shall nevertheless be valid and sufficient for all purposes to the same extent as if he had remained in office until and including such effective date.