However, due to the extremely rushed nature of the first half-dozen episodes of “Final Act”, in the anime version he simply reveals himself, then flies off. In the first episode of “Final Act”, Goryoumaru reveals himself to be, to the surprise of no one, Mouryoumaru. The answer is a definitive “yes” to both of these. I see a lot of questions along the lines of “Does Sesshoumaru know that Inuyasha turns human?” or “Has Sesshoumaru ever seen Inuyasha in his human form?”
Manga - The Lost Chapters - Sesshoumaru and Human Inuyasha