I was thinking that Legend Lore might not be effective as a means of gathering information that was held as a close secret by the Scribblies. But then I remembered that the dungeons were constructed by crews... or at least Dorukan's was, and we saw Serini supervising the delivery of a cage of monsters. (The literal accuracy of that page is uncertain.) It would depend on whether Kraagor's Gate was hidden before the dungeon work began.