GABELLI GROUP CUTS GENCORP <GY> STAKE TO 6.3 PCT A group led by New York investor Mario Gabelli told the Securities and Exchange Commission it cut its stake in Gencorp Inc to 1,410,184 shares, or 6.3 pct of the total, from 1,626,233 shares, or 7.3 pct. The Gabelli group said it sold 216,049 Gencorp common shares between March 20 and 30 at prices ranging from 108.75 to 114.75 dlrs a share.