The front plastic piece is screwed to three hinges at the bottom. Inside is some hilarious instructions for installing new carts. Looks like you aren't supposed to install or remove carts with the unit plugged in, and make sure the carts seat 1mm from the top edge.
And finally, the finished front. The cart titles are visible through the little windows.
Here's the finished guts. The menu cart board is plugged into the socket on the main PCB, and the power supply is installed. Yes I was holding the front up with a piece of wire for the pics. :-)
I'll be putting up the rest of the pics once I replace the two keylocks on the front. This unit did not come with keys, so putting it together or opening the front would be very very difficult. I'm hoping I can find some look alikes at a hardware store or something.