Roy was hit harder in fights vs Merqi Sosa, Lou Del Valle, Montel Griffin, Eric Harding and even Hopkins than that left Tarver stopped him with and many of the punches that would drop Roy later in hia career
Prime jones was barely touched in the chin so i doubt that it proved that he had a good chin. Having great reflexes has nothing to do with a good chin. Floyd patterson had a MUCH better chin than jones. Only stopped by Liston,ingo.and Ali . took shots from guys like archie moore,jerry quarry or oscar bonavena. Glass chin my balls
A chin can deteriorate with age. Sugar Ray Leonard in his fight with Hector Camacho is an example of this.
An absolute prime example is Mustafa Hamsho. At the time of the first Hagler fight his chin was rated virtually the best in boxing. It aged.