Yours is a bit taller than the concept - pretty much caused by that extra screw. There seems to be some odd pinching around the inset screws. (The screws are flush in the concept...)
As others have said, the screws should be resting on top of the metal plates, and not look like they've been punched in, bending the material underneath. They are screws after all, not rivets. The screws on the head have a round groove around them in your model. This way, they would not hold anything together. In the…