71 K5 CST - Whats it Worth?

[Rack Man]

I have been looking for a 1st Gen Blazer for a long time...Stumbled on this one...Its a one owner...the guy bought it new, but its not a Survivor...It looks quite a bit better in the pics than in person...but its still pretty cool..A couple details.

Repaint of non original color - Paint is pretty nice except for on the Cap (flaking)
non original motor...GM Goodwrench
Non original front buckets
Non original steering wheel
Has all paperwork and protecto-plate
Rockers have been replaced - Rocker boxes were not - but need to be
Bottom of doors and door corners have some decent bubbling happening
No other Rust or Bondo - Been in AZ for the past 40 years - Bought new in NJ
Doors have been cut for 6 x 9 speakers - as has the Dash
Runs great and can driven anywhere

Guy wanted $18.5....I left and said no way...he called today and told me to make him an offer...my first thought was $12k.....It would eventually be a total resto project for myself....Is it worth $12k?