I don't think he was referencing having found black/red/silver that are ALSO a Brooklyn or NNO, rather a base mini of this variation. I've pulled a base Brooklyn back from an X case, and guessing my experience is far less than the previous commenters.
Got it, could you post a photo of the base brooklyn back you pulled. Is it regular size or mini?
Mini. Admittedly it was of a baseball player (?!) so I didn't give it much thought. Check out some case/box breaks on YouTube of Ginter X. I've seen a few of each variation pulled on camera.