I'd be interested in their reaction when you call them out on the model year. Either they honestly didn't know (but should, being a bike shop) or they were trying to pull one over on you. Either way, it makes me suspicious of the shop. Not that they aren't a good shop, but just proceed with caution.

Plus, if you call them out on it, they likely won't try to pull a fast one on you again because they will realize that you know your stuff.