It's a 2 piece design, I'm 99% certain of it. There wouldn't be any way to install the plate in the bottom pic if it wasn't. If I can make a few more sales, I'll order one of these to try out. I ran an airsoft one on my rifle and loved it. That one was a 2 piece design too btw.
Here's an old pic of my setup... Fun little bastard to run out at medium ranges