One of the highlights of Gwok Jing's youth in Mongolia was when he famously shot down two condors/eagles with a single arrow, thus giving his story the title LEGEND OF THE EAGLE-SHOOTING HERO (aka LEGEND OF THE CONDOR HEROES). It was a feat witnessed by Mongolia's royal family and generals, and made Gwok Jing something of a legend in Mongolia.
Nobody in the Chinese wulin ever saw him do this, however. Gwok Jing did this long before he entered wulin. Nevertheless, by the time of ROCH, Gwok Jing was widely known as the "Eagle-Shooting Hero." How would people in Chinese wulin even know about Gwok Jing's eagle-shooting exploits? They didn't talk to Mongolians, and it's doubtful that Gwok Jing went around bragging about his archery skills to people he met in wulin. As much as it was a highlight of Gwok Jing's youth, the eagle-shooting incident would probably not have been known to wulin people.