[quote=@Kazemitsu]
I remember seeing a picture of Tali on the ship. I don't recall horn-like protrusions on their noggins o3o
[/quote]

There was a mission where Shepard learned about the beginning of the Morning War. If Shepard romanced Tali, Shepard brings up about how all the quarians are wearing the suits even though they don't have to. An AI or whatever tells Shepard that just because Shepard seen one doesn't mean Shepard can know what all look like. So since Shepard knows what the suits look like that is what Shepard sees.

Some quarians might have horn-like protrusions just don't know.