(a) The name required by the Act to be used on labels shall be the name under which the manufacturer of the wool product or other person subject to section 3 of the Act with respect to such product is doing business. Trade names, trade marks or other names which do not constitute the name under which such person is doing business shall not be used for required identification purposes.

(b) Registered identification numbers, as provided for in § 300.4 of this part (Rule 4), may be used for identification purposes in lieu of the required name.