I could be wrong, but it looks like the mobo is actually sitting on the box it came in? It looks like they use zip ties to keep the wood in place, sat the mobo on it's original box, and used more zip ties through the mounting holes to create tension. I've seen worse, but I would probably just drill and mount stand-offs to the wooden base. Might be a good idea to glue the wood in place also. Too much zip tie action all around for my liking.
Hmmm it does sorta seem like there's wood underneath, but the case didn't include any, it was only the metal frame.
Here's the actual listing on eBay (just updated my original post):
https://www.ebay.com/itm/Aluminum-Open-Air-Frame-Mining-Miner-Rig-Case-For-6-GPU-ETH-BTC-Ethereum-ZCash-/312006948420