G'day Paul.
Cool story.
I this the one? Appears to be CSX 4048.
http://www.piccola.com.au/documents/SHELBYCOBRA.pdf
http://www.piccola.com.au/sa-sales_listings.htm
Cobras built in the 60's and a handful of continuation Cobras from the 90's (I believe) had the CSX 3*** designations.
I'm surprised he managed to get it registered. You know what they say, where there's a will there's a way and a loophole of course!
For sale at $580,000 Aus however is somewhat rich though!!!! You'd think he'd have built the interior/dash with far more authenticity, especially for the money he's asking for.
Absolutely stunning none the less.
Regards.
Steve.