I'm just speculating. This is one of the nicer ones, it seems. Whoever is making these is getting better at it... for better or worse. But there are some details in the pattern of the hamon that I think I recognize as being consistent across a lot of the blades from komonjo. Specifically, the rounded tips of the choji "bulbs" have a very particular definition and shape.
It's worth at least as much as you've bid. There isn't anything in the reproduction market that comes close to this one. But if you start approaching the $1K mark on this, I'd say you'd be better off buying some nice tosogu. Just my 2 cents, such as it is.