Hi!
There is no way to tell from the VIN
The Vin should start with 8R01 but that doesn't tell you it's a Special. The 8R01 will tell you
it's a 68 (8) and was built in San Jose (R) as a coupe (01).
If it doesn't start with 8R01 you know it's definitley not a CS.
To prove it's a CS the only way is to order a Marti Report.
http://www.martiautoworks.com/
The Production report is what you want.
If you find something you're seriously planning on buying pay the $17 for the basic report to confirm.
They'll even fax it to you for an extra $10 if you need it quick. It's well worth the $27 to confirm.
You can always upgrade the report later.
Check out the thread here on Marti Reports if you're not familiar with them.
And Welcome to the Site!!! Good Luck!