Why wouldn't he be? He trained as a boxer his whole life and was a legitimate world champion at 130. If nothing else, old boxers always have their toughness and their muscle memory.
I hear you but I always get it from guys who have never been in a ring before that they could kick this boxer's ass or that one. I remember back when I was an amateur guys who thought they were bad came to the gym and thought they would kick some ass. I used to lick my chops for these types and as soon as we got into the ring and with the first or second body shot landed they would fall to their knees and most would never come back to the gym again.