As any good Trek nerd knows ,Doohan and thus Scotty by proxy was missing a middle finger. Granted his missing finger didn't impact the stories much but we know for a fact it is canon because anything on screen is canon and his missing finger can be seen(or is that not seen) in some ep's like "Trouble with Tribbles". I for one expect the movie to respect canon and make Scotty have a missing finger. Also I don't want any excuse about how he might have lost it later on due to this being a prequel. Granted it is plausible but since Shatner isn't in the movie they owe us another homage to "TOS" to make up for the lack of Shat in the movie and I want this to be it.