Stamping signature on notices or bills.

Every notice or bill, which is required by this Act or by any rule or regulation made thereunder to bear the signature of the

22[Secretary] or any other member or of any officer or other employee of the Board, shall be deemed to be properly

signed if it bears a facsimile of the signature of the

23[Secretary] or of such other member or of such officer or employee, as the case may be, stamped thereupon.