I don't see why. He doesn't mention it at all until Goku is already Golden Oozaru. He says that if Goku can gain control of himself, he will become a Super Saiyan 4. That's the only direction he gives about it, while he and Shin are watching through the crystal ball.Saiyan said:Old Kai knows the Ssjin4. But he thought by achieving it, Goku will just have to transform to do it like the other forms. But Ssjin4 required to pass Golden Oozaru to reach it.