dont know if true... but woudln't rule it out.   they had a billion dollar machine with the beatles.  It was the 1960s.  With money, one could replace and nobody would notice.  Back then, quite a few people noticed... but without the internet, it just went away with time.  
if i'm in a band and we're the top band in the world, and a member dies, and we have opportunity to quietly replace him and make hundreds of millions... it's a no-brainer, really.  
they changed out the main guy on the Wiggles, and most kids didn't even notice.  But I did.