Obviously it works we see it in the picture there but I did contact Go Rhino to ask about it and even though on their website it says universal for midsize trucks it isn't made for the Gladiator. No idea why not but that's according to them.
It's not a tonneau cover. It's a system that bolts in and is supposed to act like a rack so you can put things on top of it like a spare tire. From what I've seen it isn't meant to keep weather out just stack gear. I've messaged them about this but haven't got a response back.