Despite recognizing Sherlock's name, and assuming that Doyle probably got some things right, Will isn't actually relying on the books to tell him much. He'll actually be surprised at how factual they are. He's more thinking this Sherlock is a modern version of James, and despite how much he respected and looked up to the man he really didn't know him that well.

"Ah... yeah. I don't always take everything into account." Like the passage of time, or sentiment apparently. Will shifts a little, leaning forward so he can rest his wrists on the table. "Look... I can kind of be a dick sometimes, so... I'm sorry about that. It wasn't fair of me to say any of that, I guess you just... surprised me."