S.E.C. MOVE EXPECTED ON NEW A.T.& T. SHARES
The Securities and Exchange Commission apparently does not like the idea of premature trading in the new stocks of the stripped-down American Telephone and Telegraph Company and those of the seven regional telephone companies it is spinning off. The commission is expected to issue an order today that would prevent any such trading until Nov. 21. That is the date that has been scheduled all along for the start of ''when- issued'' trading, which is trading of stock before the certificates are issued. A spokesman for the commission declined to comment.