GENCORP <GY> FIXES RIGHTS SEPARATION DATE Gencorp Inc said that because it is continuing to evaluate General Acquisition Inc's tender offer it has fixed April 3, subject to further extension, as the date the rights to purchase preferred shares will trade separately from the common stock as a result of the tender offer. This extension of the expiration date is conditioned on no person acquiring beneficial ownership of 20 pct or more of Gencorp's common stock prior to April 3, it said. Gencorp said it could distribute the rights certificates to shareholders 10 to 30 days after the March 18 acquisition offer was made. However, rather than leaving the expiration date in a range, the board decided to set April 3 as the day it will distribute the preferred share purchase rights.