Well, I tried to say something nice about John Deere, and look what happened? Maybe they're not so much of an improvement as I thought. I can see that if the front hood support isn't adjusted properly, the bottom left side (in the photo) wouldn't engage the tabs of the side cover. Army, I'm not implying that you don't already know this.
For the benefit of others, I had a heck of a time the first time I put all of this together as the same condition existed. There are actually three adjustments that need to be made to attach the side covers properly. The four hood support bolts need to be tightened after the side panels are in place. Then rock the hood support so it lines up properly with the front edge of the side cover. Now if the hood hinge brackets have been loosened or removed, they need to be adjusted so the hood fits properly over the plastic dash panel. That was the hardest part as I had to reach up into the hood while closed to tighten those hinge bolts. Then, there is enough available movement in the speed nut where the one-side cover attachment bolt fastens.
I had that hood off numerous times since I first installed it, and now take it off with the hood support left attached. I still have to install the side panels to get them to fit properly but at least I don't have to mess with those hinge bolts.