Are you sure that display cars had these exact dents (on same locations, i.e.)? If this is the case, then it is likely to be a manufacturing fault for a batch. But it is strange as these dents would have been spotted in the Quality Checks easily.
If it is not the case with other cars, then your car might have been damaged during transit, as atlex123 said. It is also likely that in the yard, someone would have opened the doors of another car (parked close by) and damaged your car. These vertical dents look like those caused by door-hitting by closely parked cars. But again, it is not possible to dent the upper portion of the rear door (in that angle)!
I would say, just ignore them. They are on the opposite side (you'll not see them everytime) and are not that prominent to carry out a repair work. A badly done repair would make things worse. Try contacting your SA and see if he can do something, like replace the entire doors (left side). It would be great if some members (and Baleno owners) can join in and check if their cars also have these dents.
EDIT - After reading the last post, I am thinking that your dealership is HAUNTED!