Many people were certain that the Tortah was authored by Moses.
Many people were certain that Mary Magdalene was a prostitute.
Many people were certain that the Pericope De Adultera was authentic.
Many people were certain that the Pastorals were written by Paul.
People claim certainty about all manner of things from Moses being a Pharoah to Jesus traipsing around India. You have two Greek fragments and a Coptic translation of a Gnostic piece typically dated to the 2nd century CE. You may like it. You may even believe it. But is remains unclear to me how you could claim certainty based on so little.
By the way, you wrote ...
Part of a conversation between Levi and Peter, concerning Mary - from the Gospel of Mary. Not that you care of course.
It was a petty and worthless ad hominem. I have a great deal of respect for evidence and have expended considerable mental and financial resources in an effort to access and understand whatever evidence suggests itself as relevant.