The vendor, Rock and Metal DJ, Haggis, said he managed to get his sleeve signed as he hung around with a couple of friends inside the venue after the show, while "dozens of frenzied Nirvana fans were waiting for them to appear from the venue stage door".
"We knew the guys who ran the Bierkeller and we were also friendly with the door staff, so all this helped immensely with me getting this LP actually signed.
"I remember Kurt saying to us, 'Is it just you three?', as if he was saying, in not so many words, 'Where is everyone else?'.
"We wanted them to ourselves for five minutes, so retorted with, 'Yeah, just us three'.
"The rest – as they say – is history," he added.
The sleeve is expected to sell for between £12,000 and £15,000 when it goes under the hammer on 16 April.
