That's right, you do have to have a performance license to get them and even then I believe you don't get to actually keep the book. My company was contracted to build the
entire set of Audreys in
three weeks for a production in the US.
I wasn't familiar with the show the first time I was involved with building them and the production they were built for "forgot" to mention Marty's booklet existed. When they arrived (and weren't exactly what they were expecting) someone ran up to me - waving "How To Audrey II" - and said "why didn't you build them like THIS?! It explains how everything is supposed to work!"
They had forgotten to tell us about the book or show us Marty's diagrams.
If he hadn't been holding my cheque I would have strangled the director.