Actually a piece missing like that from a clutch is not a good thing and would screw up the balancing and with it out of balance then the crankshaft. Most likely that is why it was in a storage and off w/e snowmobile or UTV it came off of. Tbh it really isn't worth anything other then maybe selling the spider, primary spring and a couple other parts. Definitely isn't worth 600 dollars
Calibrated, meaning balanced with the correct weights and primary spring they go for around 700 brand new in box.