According to the books he did wear a metal skull cap, that simulated his natural hair, for protection.
I like Doc's musculature of the Ballentine books, but like the old pulp magazine face better.
This is more like how I see him...
I hope if they ever do the new movie about him they go with the retro looking Doc before the Arnold/muscle bound looking Doc.
Sorry about that second picture earlier. It appears that some sites do that when you hotlink to their pictures.