Well, it has no basis in fact.
How do you imagine that they could keep that one under wraps? Just wondering.
True, there may be a few uncredited musicians on particular pieces, but The Beatles definitely played on their albums.
And their influences have been well-documented too. The BBC doc
John Lennon's Jukebox (click for full video), for instance, is relatively recent and chronicles various song elements John lifted from some of his faves.