At 135 and 147. And out of curiosity how do you rate both men at the weightclasses they each fought in?
Napoles destroyed your average pressure fighter, see his fight against Adolph Pruitt for example. Armstrong however was not your average pressure fighter. His style could be ideal to breaking Napoles's usual rhythm. Napoles had the power, the accuracy, the counter-punching and the durability to discourage most boxers from taking the fight to him but I think Henry Armstrong could be one of the few who could successfully pull that off. He did it to so many good boxers that you can hardly doubt him. A rough fight where both men would take a battering, with Armstrong having his hand raised at the end. Some may disagree with the decision based on Napoles's cleaner work.
Armstrong did tend to use that head as a third fist, which automatically means a loss on cuts to Napoles.