I don't know what to make of this.
http://www.retroist.com/2010/11/08/1978-style-star-wars-spoilers/
When the first Star Wars movie came out, my family was living in Sunnyvale, California. My mom quickly realized that, at 7 years old, I was a huge Darth Vader fan. Prior to seeing the movie, I incorrectly thought he was Darth Fader (allowing him to fade through walls and attack his victims). For this particular 7 year old, who had heard his friends speak of the movie, and tell of various Force powers, this fading ability made sense.
Anyway, my mother was good to keep an eye out for Star Wars news – and when this particular item showed up in our local paper, she cut it out for me. I still have it to this day. And, it was my first introduction to spoilers. In late 1978, David Prowse revealed that he was Luke’s father – two years before Empire Strikes Back hit theaters. In retrospect, I wonder how George Lucas felt about this. Since there was no internet in 1978, he probably never knew that David was running around spilling the beans. This article was quite the shock to my 7 year old system. Could this be correct? Were they related? Was David playing a joke? Was the post-Watergate media trustworthy? I had to wait two years to find out.
These days spoilers are pretty much inevitable. But, in 1978, this was big news. Eventually I decided that I believed the article, and shared the news with my friends. They mocked me for making up such a crazy idea. Luke related to Vader – simply impossible. A while later we moved, so I never got to gloat that I was right about this when Empire hit the theaters. They probably forgot all about it. But I was right. I have the article to prove it. Why didn’t I think of showing it to my friends back in 1978?
This article was published in 1978 and Prowse clearly already knows Luke is the son of Vader. Doesn't this go against everything that has been said about Prowse being kept in the dark as far as the big reveal ie the line of dialogue used on set being Obi Wan was your father etc?
If this is true I can see why the Lucas/Prowse grudge exists.