said by RobinK:
No, it was never announced.
George Lucas said he is ending it with 6 movies because he wanted to end it with Luke and Anakin's story. He never really did know what he wanted to do with the franchise.
Just because George Lucas talked about it 30 years ago does not make it official. That is not how it works.
Obviously its been lost to time, but back before 1-3 were even made he said he was going to do 7-9 later, but later announced that 1-3 was it.