Section 3: Certificate to be conclusive evidence.

If any question shall arise as to whether or not-(a) such order (to which section 1 or 2 of this Act relates) was issued or made or purported to be issued or made; or
(b) any act, matter or this was done, or purported to be done, pursuant to such order, a certificate issued by the Secretary to the Federal Government shall be conclusive evidence of the matter so certified.