If the manufacturer or, in the case of foreign made products, the importer or domestic sales representative of a foreign manufacturer, of any product covered by this part furnishes the information required or permitted under this part, then any other seller of the product shall not be deemed to be in violation of §432.5 of this part due to his reliance upon or transmittal of the written representations of the manufacturer or importer if such seller has been furnished by the manufacturer, importer, or sales representative a written certification attesting to the accuracy of the representations to which this part applies: And provided further, That such seller is without actual knowledge of the violation contained in said written certification.