I am listening to the Los Angeles Jazz Institute CD (LAJI-0010) titled "Howard Rumsey's Lighthouse All Stars On The Air 1957". The CD contains two sessions broadcast on November 20 and December 18, 1957 on the KMLA radio station "Nightlife" program. These sessions are very, very good and is it possible that other KMLA radio broadcasts are available?
An interesting fact is that KMLA was an early FM radio station. The recording is not in stereo.