https://www.ebay.com/itm/16382170237...cAAOSw3IxdVwg5
...is a current listing for a steel framed Spectrum, by Kellogg, which is a more recent vintage, and all Campy components.
I was surprised to find it on there, because mostly what you see are his titanium frames, which go for more.
Anyway, you wanted comparables on pricing.