Yes the center panel is just bolted in. I have removed the passenger bench seat in those (bad) pictures because I replaced it with a new bucket seat.
Mine came with the air shift, I was only replacing the T-case because one of the bearing cages came apart (discovered during initial fluid change after pickup from GL), It was actually still functioning fine when I removed it.
Just another example of it runs and drives from a GL auction, turned into multiple brake issues (new air pack, etc.) and a bad transfer case. Oh and one dry inner bearing. They packed the outside one, but forgot to repack the inside bearing. I wouldn't have known if I hadn't pulled it all down and put in new boots, seals and repacked everything (along with a new bearing and race for the damaged one that I found.) All fixed now, but just a warning to novice GL auction buyers. They can look brand new and even drive around the lot in the videos, but still have thousands of dollars of needed repair and maintenance.
With that said, I am off to pick up my new 5 ton. First walk through inspection looked great, now I just need to do final safety checks to see if I can drive it home today and start changing fluids, filters, and all the stuff I have to do so I know the truck is 100%