FIRM HAS ALLEGHENY INT'L <AG> PREFERRED STAKE Spear, Leeds and Kellogg, a New York brokerage partnership, said it has acquired 136,300 shares of Allegheny International Inc's 11.25 dlr convertible preferred stock, or 7.1 pct of the total outstanding. In a filing with the Securities and Exchange Commission, Spear Leeds said it bought the stake for 11.7 mln dlrs as part of its normal trading activities.