and another question: i bought a bootleg form 'live Köln WDR, 22 März 1975' entitled 'Kometenmelodie 3' => is this "3" an error or is this on all copies of this concert?

It's on all copies, so I suppose the bootlegger simply thought the title was funny. It's the same concert as on the former "Kometenmelodie" LP and the "Super Golden Radio Shows" CD. I like this recording very much. The sound quality is above average (radio broadcast) and the performance is fantastic.