Are there any other copies of this video out there? Since it's a bogus claim, the video should be able to be posted elsewhere --- YouTube can't be the only source of record.
They don't but if it is a popular video the likelyhood of it being archived increases. It is possible to submit URLs to archive.org manually too. Also the youtube videos downloaded by archiveteam volunteers[0] possibly end up in wayback machine though I'm not sure if it happens automatically anymore.