it depends on the dealer and what person does the pre delivery prep job
mine are screwed both front and rear i have lost count the amount of time that next doors plates have fallen off, told them to get them screwed on
As a very recent owner of a preloved note (but lovely and new to me) I've just checked mine-front number plate fixed with two screws one in both top corners. Rear plate two screws again but these are midway set in a small distance at each end of the number plate -hope that makes sense and helps!
As a rule, the stuck on plates get pulled off and stolen, then end up on a garage forecourt cctv attached to a car that drives off without paying, presumably you only need the back one with where the cameras are located.
I did hear about super sticky plates that break apart when someone steals them, so at least they can't be used.