Love my Hardtopped Comet! Price wise, decent Comets don't seem to sell super quick when priced $1000-$1500. This Hardtopped one went in 1 day with an asking price of $2200...
https://pinside.com/pinball/market/classifieds/archive/85758
I paid $1000 for mine before putting on the Hardtop. I'd say it looks to be in similar condition other than Freeplay40's corkscrew (which I now also have). If that really sold for $2200 and I could sell mine for a similar amount. That would mean the Hardtop added about $1000 to the value.
Here is another, but even more fixed up, this one was $2500...
https://pinside.com/pinball/market/classifieds/archive/85131
Sounds very much like mine, minus the cab repaint (maybe some day).