At first sight, a bit of both.
There are L-Shaped metal brackets holding it all together but in some places there are also triangular wood wedges reinforcing the angles which are probably glued.
If you're interested I also have a stripped down one, just the wood and the power supply, no monitor, no marquee, no bezel. It's the same cab model but the side just features the Taito stripes, no Space Chaser art, and some Lunar Rescue stickers.