One cylinder low like that on a compression test would normally indicate a valve that leaked some. There are things you can do to get a problem fixed temporarily if it's a ring but not if it's a valve unless there was a carbon build up. Assuming that the dealer is not completely dishonest I would say they got the problem.
Sometimes the carbon build up could be from a valve stem seal leaking. If that's the case it will reoccur. The other source of carbon would be bad fuel mix, and you need to know why that would happen on a new engine.
Not much help, I know, but if you get some others with that engine they may tell you if #2 is a problem cylinder or not.
What they tell you could be exactly right but it should not be normal.