It's a "ura" Mach Wheel, which was a sports option part. Often seen in Z432-R's.
I was watching it last night when it was priced around $900 USD, I don't know if it actually sold at that price. Or if it's real or a clone/reproduction?
The hub kit with horn assembly is around $300 USD on it's own (reproduction).
It's possible it didn't meet reserve and I've noticed Yahoo! Auctions sometimes shows the price after auction as the reserve price (or some inflated buy it now price). However these have been changing hands many years ago for $3000 or so.. (originals) but reproductions have since become available.
I've got a black reproduction. Still need to get the Hub assembly and horn for it.