The (?) is there because I don't know if the novel depicted this, or if it's a TVB innovation for LOCH '82 (it's got a TVBish feel).
We know Gwok Jing and Prince Yeun Nan Hung Lit of the Jin Empire to be mortal enemies. Yeun Nan Hung Lit was the true murderer of Gwok Jing's father, Gwok Siu Teen, and one of the leaders of the Jin Empire that threatened Gwok Jing's beloved home country of the Sung Kingdom. As unfathomable as it seems, however, these two *almost* became friends.
Gwok Jing was instrumental in saving not only Temujin's (Genghis Khan) tribe when they were threatened by the Naiman tribe, but also saving the two visiting Jin princes (Yeun Nan Hung Lit and his brother, Yeun Nan Hung Gei). Yeun Nan Hung Lit was quite impressed with Gwok Jing's courage and archery skill, and wanted to recruit Gwok Jing to bolster the Jin forces. For his part, Gwok Jing (at that early stage) had no particular reason to hate the Jin prince. Gwok Jing knew nothing at that point of Yeun Nan Hung Lit's involvement in the death of his father, and the Jin Empire was some distant, abstract political entity rather a hated enemy in Gwok Jing's mind at the time. Until Yeun Nan Hung Lit discovered who Gwok Jing really was and the potential threat that Gwok Jing posed to him, a friendship between the two was not out of the question.
Now if none of this happened in the novel, it's all moot, but in any case, it's interesting to imagine these two being friends.