It being a non-indie Vita title should be reason enough to believe it's fake. I still haven't even played the last GoW yet either, Sony needs to chill with this series.
I doubt this is true... It's too soon for Sony to reveal another instalment. I'd like the GoW series to take a good 3+ years off and come back with some significant changes. The world really doesn't need another God of War game if it's just going to copy the format of its predecessors wholesale.