I am usually more worried about the way the boathands handle my housing than scratching it on the coral.
I'm pretty sure the boathands that handle my Aquatica housing get surprised at the weight of the housing and tend to put it down on the deck with a little more force than they intended.
This housing "rash" has tended to concentrate itself around the lower edges of the housing and is chipping off the powder coated paint on the corners of the housing. Thankfully, the fine people at Aquatica had the foresight to place a layer of anodizing (?) on the housing before powder coating the housing.
Placing a plastic "skid plate" on the bottom of the housing may help you avoid the "housing rash", alternatively, a few layers of good old duct tape will work just as well but will have to be changed after about ten or twenty dives.
Hope that helps.