Nikon Rumours is full of fun stuff these days.
My own experience with third party grips for the D810 would likely make me steer clear. Twice, I ordered third party grips through Amazon, and ended up sending them back. The fit and finish just wasn't there.
When I accepted that getting the real McCoy was simply going to be more expensive, I ordered it through Amazon also. Got a nice discount because Nikon was gearing up for the D850. Never looked back.