Thanks to John Carvill:
“Maybe the discerning Dylan fans who read the Dylan Daily can help with this query?
“In Michael Gray's Dylan Encyclopedia, he refers to a 1969 Rolling Stone interview conducted by Jann Wenner, in which Wenner hadn't realised that Dylan was putting him on until it was pointed out to him later that when he used the phrase 'unload my head' and Bob picked up on it, saying he should use that line in a song, Dylan was fully aware that he'd already coined the phrase himself in 'From a Buick 6'.
”Now, as 'excerpted' here, the transcript of the interview would seem to bear Gray out:
http://www.rollingstone.com/news/story/5938145/the_rolling_stone_interview
”Yet in the 'Bob Dylan - The Essential Interviews' book, published by Rolling Stone (under the Wenner Books imprint), the exchange about 'unload my head’ is expanded to include Wenner pointing out to Dylan that he had used that phrase "in one of your songs on 'Highway 61'".
”So, is this revisionism on Wenner's part, an attempt to make himself look more alert? Or is this a genuine transcript, meaning that Wenner wasn't so fooled by Bob's put-on as Gray believes?
“Anyone got any clarifying info? A copy of the original magazine?”
(Editor’s note: the version of the interview included in the book Bob Dylan - The Essential Interviews is much longer than the online version linked above – the ‘unload your head’ passage is one of many additional passages in the book which are not in the online “excerpt” - Gerry Smith.)