Yes, Virginia, it kinda is.
George Lucas has created much myth and legend about the number of Star Wars films. He’s stated things in the media that showed he intended to make many Star Wars films and indeed at one time he did say:
“As I was writing, I came up with some ideas for a film about robots, with no humans in it. When I got to working on the Wookiee, I thought of a film just about Wookiees, nothing else. So, for a time, I had a couple of odd movies with just those characters. Then, I had the other films, which were essentially split into three parts each, two trilogies. When the smoke cleared, I said, 'This is really great. I'll do another trilogy that takes place after this.' I had three trilogies of nine films, and then another couple of odd films. Essentially, there were twelve films.”
That’s the legend but the mythology of it has grown over the years. The nutshell is that Lucas wrote a great deal of material when he was developing his little sci-fi adventure. Based around a so called “Journal of Whills”, Lucas script eventually was cut up and Star Wars as we know it was filmed. It was not until Empire Strikes Back came out that the term Episode 5 was mentioned officially.
So basically wee Georgie wrote and wrote so much material he had mapped out a series of films in his mind. Were they fully realized visions? No.
This penciled planning on the infamous 'yellow binder' shows exactly how far George actually went:
Which is to say not very far. It would appear he said too much to the media about all these films that the concept of them all stuck around and he simply had no choice but to keep up appearances. He eventually said he would do 9 films – as he knew of 3 trilogy stories he wished to tell – the others were simply one offs about wookies or robots. The most excellent website Secret History of Star Wars was has the full history here.
And to his credit Lucas actually ended up making 6 Star Wars films – more than any fan could dream of really!
As part of the sale of Lucasfilm to Disney it is understood that part of the deal included access to the treatments that George had RECENTLY prepared for the third trilogy of films. Those treatments may one day see the light of day and we’ll see just how far Lucas did get in developing the movie’s plot lines.