After opening up POLUtils, ギサールの野菜 is definitely Gysahl Greens and definitely not Rarab Tail.
I'd assume the "something a little fake in there" from that post to mean "j/k I just made that up lol" but I don't speak crazy talk so I dunno.
I still maintain my stance that SE probably didn't decide to choose some ancient item with no known recipe to be the pop item for this.