INVESTOR HAS 8.0 PCT OF ALLEGHENY INT'L <AG> A group of firms and funds controlled by New York investor Mario Gabelli said it has acquired the equivalent of 882,507 shares of Allegheny International, or 8.0 pct of the total outstanding. In a filing with the Securities and Exchange Commission, the Gabelli group said it bought the stake as part of its business and not in an effort to seek control of the company. It said it may by more shares or sell some or all of its current stake. The stake includes 782,000 common shares and cumulative convertible preferred stock which could be converted into 100,507 common shares.