Apologies for sticking my nose in, but if it's any help in establishing a starting point for price negotiation, I've seen them advertised here for prices ranging between €150 and €250 (that's Euros, not Aussie bucks). I guess the variation in asking price reflects the condition of the bars and the avarice of the seller.
Bear in mind they're the asking prices. No idea what any particular set of bars actually sold for, but I suspect not much less as they seem to sell very quickly.
If you want to do your own search, they're generally known as "Brevettato" bars because that's stamped into the middle section of genuine Laverda ones. Brevettato isn't a brand name. It simply means patented.
There are aftermarket versions that don't have the Brevettato stamp, but they don't fetch such high prices.