Except as provided in subsection (b), section
4221 shall not apply with respect to the sale of any article unless the manufacturer, the first purchaser, and the second purchaser (if any) are all registered under this section. Registration under this section shall be made at such time, in such manner and form, and subject to such terms and conditions, as the Secretary may by regulations prescribe. A registration under this section may be used only in accordance with regulations prescribed under this section.