That's a pretty big leap based in a fairly ambiguous sentence.
Just out of curiosity, since I've never seen one for my Mac, does anyone know if a manual like that exists for the rMBP 15" retina like the pdf linked in #21? I've never seen one, and searching Apple's site just came up with a much more basic introductory guide.
The question is, why isnt he confident if its an official part.
And why wouldnt he label or tell you its a official part?