Answered already, so it's no longer a guess, but the rest will remain ...
From what I gather, Gnurk-Ogh's studies would have been done in seclusion with one of a race with a strained relationship with mankind (putting it mildly) ...
And, after 600+ years, any knowledge of him would be as obscure as that of dragons themselves, no?
That's my assessment anyway ...
I have been wrong before ...
