lol, I'm guessing you've not heard of him before.
If Gurman reports something that doesn't turn up, it's usually because the product got delayed/cancelled. Check out his WWDC roundup from this year or last.
Or his piece on the new MacBook two months before it was announced:
http://9to5mac.com/2015/01/06/macbook-air-12-inch-redesign/
Not saying he's flawless, but his reporting is very on point.
Yeah, I heard of him and I'm aware of 9 to 5 Mac, although I don't read it. Reckon it's like Frank said, pretty safe predictions here with the Watch 2.