Hi Filippo,
There port and starboard sides on the model are not quite correct. It is not easy to see the pattern but you should be able to identify the port side from a combination of these two photos -


I don't have any photos of the starboard side but it can be seen in this photo of U 564 -

U 564 is from the same shipyard as U 552 (B&V). The characteristic of this B&V pattern is the two gaps.
Cheers,
Dougie