I got a 2x3x1 and a 4x2x1 and both came fully assembled.

They really are pretty nice. At first I didn't think I'd like the acrylic swinging doors, but now I'm totally sold. My AP T8s all have the sliding glass, and they rattle incessantly. Even if I walk by the snake room I hear then rattle. I needed to wedge Q-tips in there to stop it but it looks hockey. The swinging acrylic, no problem.