Based of the biased nature of Cspan with its seminar callers and 100% 'RAT moderators, I wouldn't expect them to admit finding this tape, even it they had it. Their programming became unwatchable when they added the politically correct phone lines while BC was running as President. I not only refuse to ever watch them, I used their support for CSPAN as the reason for my droppiing cable a few months ago.
During those days C-SPAN was largely frequented by conservatives as it was the only avenue available at the time and was the choice forum for Republicans to use in their one hour speeches (ultimately resulting in then House Speaker Jim Wright ordering the cameras pan the otherwise empty chamber to "reveal" those evil pubbies were speaking to viewers at home and not the house as a whole)