Replica bags are often poorly constructed and are not the same boxy shape as the original 2.55. Compare the authentic and replica corners of the bag below.
You can clearly see how the replica bag’s corners are more rounded. This is a sign that the bag has not been turned out properly. An authentic version is more square. It is worth noting that very old and well used authentic bags will loose their shape slightly.
Fig 1. Authentic bag corners are square shaped
Fig 2. The replicas bag’s corners are more rounded