Very little of this literature survives in more than one copy. The Apocryphon of John survives in four: Nag Hammadi Codices II, III and IV, and the Berlin Codex, a manuscript bought in Cairo in 1896 and published only in 1955, decades after its acquisition. All four are Coptic translations from Greek and all are usually dated to the fourth century as objects.
They do not agree in length. Codices II and IV carry a longer recension, Codex III and the Berlin Codex a shorter one, and the difference is not a matter of scribal slips. The longer version contains substantial extra material, including a catalogue of angels assigned to the parts of the human body, drawn from a source the text names, and the closing Pronoia monologue. Whether the long version expanded a short original or the short version trimmed a long one is disputed; the presence of a named source inside the extra material inclines many scholars towards expansion, but the four copies are close enough in structure that the underlying work was clearly stable in outline while remaining open at the seams.
The dating rests on an opponent. Irenaeus of Lyons, writing Against Heresies around 180, summarises a system involving Barbelo, the aeons, the erring wisdom and the arrogant creator that matches the first part of the book closely enough that he was almost certainly using this text or its immediate source. That puts the material no later than the mid-second century, well before any surviving copy, and makes the Apocryphon one of the few works of its kind that can be pinned to a date by external evidence rather than by argument from style.