We are going to install a dutch door as well, and I'm trying to figure out the hardware on this photo. It appears as though there is a deadbolt for the top door, a lock to lock it to the bottom door, but is that also a lock on the very top of the door?

Also, does the door handle for the bottom door have some type of deadbolt as well? That seems like a thick piece of hardware for only a door handle lock.

Any advice you could provide quickly would be greatly appreciated. This might be the type of setup we are looking for (especially whatever that is on the very top of the door).