Apparently, the gravity waves cause polarity in the back ground radiation. This, I think, it is the first time that the effects of gravity waves were observed. We have not yet directly observed gravity waves in the lab.
Now, when it comes to 'predicting' anything, you can say the bible predicted anything you want, after the fact. Now, showing a prediction for something that isn't known and accepted before hand, , that is different.
Shoehorning a concept into place after the fact doesn't really say anything.