Never trust the memory,
the old listing has disappeared from ebay and I can't find it in google cache, but the item heading in the old emails from when I won the item are:
"KTM LC4 620 640 Radnabe Nabe Vorderrad (front wheel hub) 17mm ,20 mm 660 690 Duke
17mm and 20mm and fitting all those models (with no year listed...)
I am not sure what information was in the item description itself...
Anyway, with the smaller bearings it fits the 17mm axle no problem. The rotor bolts up and the correct offset for the caliper should be easy enough to figure out with wheel/axle spacers.
By eye the spoke holes between the two hubs appear to line up perfectly so I am hoping it is a japanese pattern.
If I could find out what hub it is, I am hoping I might be able to figure out what spokes to order, rather than handing it over to a wheel builder (which I can't afford at the moment),