Never seen either of those two but Hagler was not all chin. Hagler had one of the best chins but his defense and his chin is what would make it hard for anyone to stop him. If you watch his fights Hagler never allowed anyone teeing off on him with hard combos. He would take single big punches and make sure the other guy don't follow up with more punches. Like Mugabi's uppercut or Hearns right or Sibson's hook. Another thing, KO's mostly happen mostly from counter punching and Hagler almost never got counter punched because of his defense and reflexes. He had underrated defense.