In THE ROMANTIC SWORDSMAN (TVB's 1970s adaptation of SENTIMENTAL SWORDSMAN, RUTHLESS SWORD), Sheun Siu Hung compared the duel between Lee Chum Foon and Gwok Sung Yeung to a duel once fought by Chor Lau Heung against a powerful enemy. If this is legitimately Gu Long and not a TVB innovation, then I've got this timeline:
CHOR LAU HEUNG------>SENTIMENTAL SWORDSMAN ---> THIRD YOUNG MASTER'S SWORD----->FULL MOON, CURVED SABRE
That seems about right, yes? No?
Now where does LUK SIU FUNG fall into that timeline?