I've been watching this ebay seller for a while now and he/she has sold multiple Bob Dylan signatures etc. all on sheet music (has one for sale now), the Jimmy Page also appears to be the same, feedback is also private, all very suspicious to me.
I genuinely don't think I have ever seen a real autograph on sheet music. It is of course the cheapest format for the fraudsters to churn out their rubbish (a photocopy from a book) - no doubt sitting at their kitchen table making several attempts until they feel they got it right. Agree with everyone else here Steve, not authentic.