Seems to confirm that someone was buried there before 200 AD...
Don’t forget that the Benedictines had found above it a memorial, “Paul, apostle, martyr.” The discovery of the sarcophagus proves it was a death memorial. The discovery of bones inside it proves it was for an actual body. The discovery that the bones were of someone who had been there for so long time proves the antiquity of the memorial.
So what’s an alternate explanation, if that’s not Paul? I mean, if you were to take the bones of some dead guy, and erect a marker declaring that they are the bones of Michael Jackson, would your contemporaries go along with you?