At the end of book 1 of the papyrus containing extracts of books 1 and 2 of Origen’s Contra Celsum, is an interesting note:
μετεβληθη και αντεβληθη εξ αντιγραφου των αυτου ωριγενους βιβλι[ων]
Revised and corrected from the copy of the books of Origen himself.
This is quite a statement, in a manuscript of the 7th century. Presumably this means at Caesarea, where Origen’s library ended up.
One interesting feature of this papyrus is that two readings are given in some cases. The editor of the papyrus, Scherer, suggests that this is because the ancient editor — presumably at Caesarea — found two readings in his sources. In other words … we have indications of an ancient edition with a critical apparatus. More interesting still, the two-fold reading makes its way even to the 13th century codex of Contra Celsum.
We’re all familiar with the colophons in biblical mss recording the editorial work of Pamphilus. It’s interesting to see evidence of the same activity on other works being copied.