Maybe more. A little unsure about this one. The same sword sold for somewhere between 500-700k a few weeks ago, and there appeared to be quite a bit of interest in it... but this is one of the more common req7 15^50 skins, and interest in celestial skins has decreased somewhat of late.
This is one of those items I find hard to predict how much it will go, depends on the potential buyers. With it's req7 and 15^50 it's the best celestial sword you can get. But I noticed celestial stuff decreased in value and popularity lately. I would start with a S/B of 100k and see where it goes.