Well, I guess I was wrong.
I read this books quite a while ago and some parts again just recently - now I browsed through it in search for guitar-stories, two caught my attention:
- George borrowed one of his first Gretsch`s to Klaus to keep as long as he wants
- Klaus visits John (around the time of the composing of "Lucy In The Sky With Diamonds" and while he waits for John he grabs one of his guitars and plays a bit.
But I couldn`t find anything about John giving the spanish guitar to Klaus.