Thanks for posting the links to advertisements, because I find it interesting to keep an eye on a car's sale history. This car has been for sale a bit over the years. It's dropped a few thousand since it sold at auction 6 or 7 years ago.
1965 ARNTZ ROADSTER COBRA RE-CREATION - 70846
Then it was here.
Ford Cobra Arntz Roadster 1965 | Brighton Motorsports | Collector Cars | Scottsdale, Arizona
And then the current owner had $35k on it...
1965 AC Cobra for sale #1829881 | Hemmings Motor News
and now it's on CL for more money!