What do you mean genuine? Is the review genuine? Yes. I'm a nobody who likes this product. Is the product genuine Amazon/Oculus? As far as I'm aware it is :) it's not a third party product.
This is the official battery/strap from Oculus. However, I would look at alternatives first.
I personally use a Rebuff VR Power 2 battery with the default soft strap. I got it after I accidentally snapped my Elite Strap.
If you want a hard strap, it might be worth looking at some of the products from Kiwi or others.
Good luck!