All waybills, transfer bills, running slips, conductor's cards, or other papers accompanying a shipment, in the course of importation or otherwise in commerce, of any product shall have embodied therein, stamped thereon, or attached thereto a signed statement which shall be evidence to connecting carriers that the proper shipper's certificate, as required by § 325.5, § 325.6, or § 325.7, is on file with the initial carrier. No connecting carrier shall receive for transportation or transport in the course of importation or otherwise in commerce any product unless the waybill, transfer bill, running slip, conductor's card, or other papers accompanying the same includes the signed statement in the following form:
Signatures of agents to statements required under this section shall be written in full.