I don;t know as a fact, but i would suggest that The Beatles would see The Rutles as an affectionate tribute, which is a world away from a money-making rip off. Remember, George Harrison was involved in the original film, which is surely a measure of how he, and the band, saw the whole enterprise.
Legally, you can't sue someone for an approximation, visual or musical, otherwise The Bee Gees and Leo Sayer, and maybe even The Nolans would have The Scissor Sisters in their gun sites as I write!
I think this is the kind of urban myth that crops up regularly in msuci, and the world at large.
Next week - Bob Holness did not in fact play the sax. on 'Baker Street' - full expose here!