Arnold Schwarzenegger in T4

Arnold has made it really clear according to a multitude of online outlets that he wants to be in Terminator 4 Salvation. There is no source posted for the quote but everyone is running the following quote accredited to Arnold;

"I've never had a dialogue with anyone about it. But if they shoot the movie in California, I would [be a part of it], yes."

I think that a cameo for Arnold in the film would not work when you consider the timeline of the 4th film. Its supposed to be based when Conner is in his 20's which would mean the Arnold Terminator character is not built or around yet.