His head was opened up by being dragged along the catch fencing, not the wall, though it amounted to the same thing. That was probably the most destructive crash ever caught on tape. One doctor said he had no unbroken bones in his body.
You are correct. I found a grainy black and white picture online once of Gordon’s body after the cockpit came to a stop.
He was sitting upright with arms and legs attached, but his skull appeared to have been opened with one of those saws used in autopsies.