Many thanks, Mike.
Peter Trunk is listed on the back cover of the Opera EP as the bass player on this date. However, according to Albert Mangelsdorff, it could not be Trunk on bass, as by that time he had left the Albert Mangelsdorff Septtet for a short time. Al King is the suggested bass player in the Albert Mangelsdorff Discography.
As for your offer to make an MP3 when you visit the Jazz Institute at Darmstadt, I will email them with my inquiry. And, again, many thanks for your help!