Appears to be homemade. This is raw C grade plywood on the inside with 1x1 bats running up the sides to support.
Real Midway cocktails had 1x2's cut diagonally for side supports set every 6 inches or so. They also were finish quality (MDF-like) surface on the inside and sprayed black.
The monitor chassis was mounted on the monitor frame, not on the bottom, the main power transformers were directly below the tube.