We've been through this discussion a number of times, and if we were able to conclude anything at all, it's this: in terms of Gwok Jing's martial arts talent, don't believe what the character says about himself or even what the narrator says about him. Just look at the results he got and the accomplishments he had. Not just ANYBODY could have done it. Gwok Jing might have been a dunce at purely intellectual exercises, and he wasn't articulate, but after a rough start with the Gong Nam 7 Freaks during his youth in Mongolia, he had the martial arts thing down COLD.
It makes it a little scary how far this guy could have gotten if he also had the brains of, say, a Cheung Mo Gei or a Yeung Gor.