When Golden-Haired Lion King Tse Tsun first appeared in HEAVEN SWORD & DRAGON SABRE, he performed several feats at Mt. Wong Poon that were utterly amazing. If Tse Tsun had lived during the time of LOCH, I don't think that anyone short of the Greats could have emulated some of the feats he performed.
Tse Tsun was not a Greats-level fighter in HSDS. The Greats-level fighters of HSDS (of which there are only Cheung 3 Fung and Cheung Mo Gei) are no worse than comparable to the Greats from the end of ROCH. Nevertheless, based on feats alone, could we say that Tse Tsun (and by extension, the other Guardian Lords of the Ming Cult) had already achieved a level of martial arts equivalent to the Greats of LOCH?