on the case-back as follow: 'P 001' or 'P 002' or 'P 003' or 'P 004' or 'P 005' and no other numbers, it must be accompagnied by its matching manual/libretto.
If there is no number on the case back then no possible doubt, it is simply a replica of some sorts, (to me) even if it is authenticated by whom ever, It is simply a FAKE.