Sorry to beat a dead horse but I've just found this article about a Star Wars bibliographer.
http://www.starwars.com/fans/profiles/20090211.html
If someone would go to this much trouble to collect every single printed reference to Star Wars, don't you think that someone would have collected every TV appearance of George Lucas? Especially a late 70's/early 80's interview in which he talks about the changes he's made to the films.
That's why we doubt this interview aired.