I recently purchased the Serotta shown in this old advert.
https://www.pinkbike.com/buysell/3723718/
I'm guessing that the man who I bought it from was the buyer at that time. I paid substantially less than half of that previous price when it showed up on CL.
Over the last couple years I've sold off all of the pre-90s Campagnolo parts clogging the drawers for something more than $3K. And I felt REALLY good about it ! I still have a couple bikes that I want to move on to new homes but I'm sure that I'll have to be just way lucky to break even on them.
AFA the classifieds are concerned, delusional sellers abound. There are overpriced C&V bikes on the NorCal lists that have been up for over a year ! One has had the price reduced all of $30 since last December.
Good luck