Also Klobrille found actual files of crosshairs for the game. It may be early development but I don't think it's fake. It was definitely in some stage of development at least.
For the game or for a game? From what I remember Klobrille said it could be for any project, he only sees the project code names, connections etc. And the rest was speculation.
I agree that MS could produce a Perfect Dark game and pass it on to another studio like they did with KI, but I doubt that what Klobrille talked about is guaranteed to be Perfect Dark, that's all.