No person shall be guilty of an unlawful act under section 70a of this title if he establishes a guaranty received in good faith, signed by and containing the name and address of the person residing in the United States by whom the textile fiber product guaranteed was manufactured or from whom it was received, that said product is not misbranded or falsely invoiced under the provisions of this subchapter. Said guaranty shall be (1) a separate guaranty specifically designating the textile fiber product guaranteed, in which case it may be on the invoice or other paper relating to said product; or (2) a continuing guaranty given by seller to the buyer applicable to all textile fiber products sold to or to be sold to buyer by seller in a form as the Commission, by rules and regulations, may prescribe; or (3) a continuing guaranty filed with the Commission applicable to all textile fiber products handled by a guarantor in such form as the Commission by rules and regulations may prescribe.