$601 does not seem bad to me for a set of Campy tandem cranks. 20 years ago when you could still get them new they sold for more than that. How rare are they now anyway and what else can you get today of that quality for less? And we've all seen Campy single bike cranks go for $900 or more.
Bob Freeman Still running one set of Campy tandem cranks I obtained in 1978 Seattle