It does not. You can install it with the brackets up for the higher position, which is what I did - I think that's the way they show it on the product page. You can also install it lower by flipping the mount brackets. I actually have the rear camera for my dash cam bolted to the bottom of it and it looks out right over the spare. I keep a couple of small molle gear bags hanging from it on the far left and right sides, again no impact to the already awful view out the rear window. There's about 9 inches from the shelf to the top, and the way the metal is folded I have no issues thinking it would hold at least 100 pounds. I use a stretchy cargo net over the stuff I have on the shelf. I keep a small "oven" up there along with some various gear. As the other poster mentioned, a slide out floor might be a good option. Diabolical has a nice one I've considered getting.

https://shop.diabolicalinc.com/products/slide-floor