Well it's clearly incomplete in this PS4 version, so maybe they'll claim it's been restored in the Switch version. I don't know, I'm not ruling out any possibilities. Viral marketing is sometimes weird and nonsensical. Morbin time, anyone?
As for the "believable proof" he showed the modders, I can't find what you're referring to. Either way, he's barely able to record and upload a video so I have my doubts.
To me, the only thing that is clear is that this dude is acting up his naivety to the internet and technology in general. In one of the posts he claims he ran out of space for the recording but yet uploaded it anyway?? Just rerecord it FFS. And his Reddit posts are nothing but "hey guize i found weird door that only i can access but not my fren pls help i" and it cuts out like he ran out of space? Nah, I'm not buying it. He's overplayed his hand. Also, his name translates to "sad twin". Gee, I wonder what that's in reference to.
Also, some guy found an 3-year old reddit post that has a cut version of the Copied City that seems to match up with the new footage
In any case, I don't actually care, believe it or not. I loved this game when it came out but that's about it. Just killing time before I head out for the day!