It will look just like the one on the Cherokee. The build tool is just a rendering and the hydro blue rendering for the Cherokee also looks a bit different.
The J6 concept is definitely a 2 door truck. You can see that it has a similar top to the rear section of the Gladiator. Also there is a light on the top that is possibly supported by a sport bar.
Im pretty sure that it is just a blue render that Jeep did off of a silver Gladiator. If you look at the bushes from the photo below they are the same.