The Board shall thereupon proceed, upon the petition, responses, and submission of briefs, to determine whether, on the facts before it, the commerce operations of the employer involved are such that it would or would not assert jurisdiction over them. Such determination shall be made by a declaratory order, with like effect as in the case of other orders of the Board, and shall be served upon the parties. Any party desiring to file a brief shall file eight copies with the Board in Washington, DC, with a statement that copies thereof are being served simultaneously on the other parties. [29 FR 15922, Nov. 28, 1964]