so it's just foam glued?
maybe i'll just cut up motherboard box instead, cable tie the screw holes into the cardboard
Yep, In past i had MB just lying on piece of cardboard. Better to use some spacers (any piece of plastic or few layers of cardboard) as well just to allow the air flow.
I feel we should warn you to not use the antistaic bag (have seen few people doing that) it's conductive.