going to take a wild guess here and give you three reasons why he didn't do that
1. its a hunting truck, so leaving it out helps protect the rear tail lights
2. if you flush mount the bumper, spring hangers would have to have been moved
3. if you flush mount the bumper, the shackles and rear of the leaf springs would stick out just as far as the hitch, causing problems since he said it was a hunting rig, and he is probally pulling a trailer with a four wheeler, rear springs and shackles could get into the trailer on sharp turns, unless you put a extended hitch on it, which is no good