I mean they both rock the maid look but Mugetsu has a bit more association with Gengetsu.
good spotting. honestly, I wouldn't know, because the drawing is monochrome. so I decided to go through the full drawing (post #5280071) and look for something that would make me sure it was Mugetsu or Ruukoto. I think I found something, Mugetsu wears a unique apron, she wears an apron cut in half in a triangular shape. I think that's enough proof to say that she is Mugetsu, not Ruukoto, thank you.