Zohar maybe not from Rashbi

I was reading the Zohar in the Berg-ite translation, and came across the following passage:

30. There are questions that are the garments of the Ha-lachah, NAMELY THE GARMENTS OF MALCHUT, of which it says "inwrought with gold" - as it is written: "The King's daughter is all glorious within: her clothing is in-wrought with gold" (Tehilim 45:14). You, AMORAIM, cut THE GARMENT INWROUGHT WITH GOLD into several le-gal sentences and later fix and explain them away using various arguments.

31. If one chapter of the Mishnah is missing, and it has been maintained that something is missing from the Mishnah, you fix it. FOR EXAMPLE, IN PLACES WHERE IT IS STATED IN THE GEMARA: "A CLAUSE HAS BEEN OMITTED, FOR THIS IS THE WAY WE HAVE LEARNED IT...," such is wanting that can be numbered. If a sim-pleton comes and spreads an evil report of the craftsman that cuts the garments, saying: The Torah is lacking - STATING THAT IN THIS PARAGRAPH OF THE MISHNAH, A CLAUSE HAS BEEN OMITTED. Yet, it is written: "The Torah of Hashem is perfect," (Tehilim 19:8) perfect in all the members of the body, the 248 positive precepts, as written: "You are all fair, my love; there is no blemish in you," (Shir Hashirim 4:7), and perfect in her garments. How can anything be lacking in the Mishnah?

32. HE ANSWERS: Say to him - look carefully and find the MISSING piece. You may find it mixed with other verses and Mishnahyot, MEANING, IT IS THE CUSTOM OF THE TORAH TO BE LACKING IN ONE PLACE AND RICH IN ANOTHER. For it is the way of the craftsman to cut garments into several pieces, AND THAT WHICH IS MISSING IN ONE PLACE IS FILLED UP IN ANOTHER. The students, inexperienced in connecting the Halachah to those pieces THAT ARE IN ANOTHER PLACE, confuse the sentences and questions, and cannot explain the dilem-mas until the craftsman comes and explains all the doubts they have. At that time, Halachah the daughter, NAMELY MALCHUT, rises before the King, perfect in eve-rything, in body, garments and jewelry. And in it the verse comes true: "And I will look upon it, that I may remember the everlasting Covenant" (Beresheet 9:16). Sometimes the craftsman has an experienced student whom he sends to correct them, NAMELY ELIJAH, AS WAS MENTIONED BEFORE.

Note that this passage, in addressing the students of the Amoraim, is clearly set after the time of R' Shimon bar Yochai. It seems to start out criticizing the Amoraim for "cutting up the golden garment" of the Mishnah, but winds up praising them for bringing the disparate parts of the Mishnah together in a coherent whole. They do this by looking for what is missing, perhaps it can be found in another mishnah or in a midrash or Tosefta, and splice it in. Or perhaps they extrapolate what was missing, as in chasurei mechsera vehachi katani - "this is how the lacuna should be read".

In any case, this is clearly the textual criticism that makes up much of the Gemara's discussion of Mishnayot. This story praises the early Amoraim for their textual activity (the early Amoraim feeling freer to emend the text of the Mishnah).

If Rashb"i lived in the late Tannaitic period (according to the JE article on Simeon ben Yohai, citing Graetz, he fled to the cave c. 161), it had to have 50-100 years after his time that this story took place. Thus, this part of the Zohar necessarily postdates Rashb"i.