Where's the VIN number 68 Valiant

Don't think so... If it was a VIN, The "V" would be the first letter, as in "VL23....

No mystery at all.

NO PARTIAL BODY VIN ON 1968 CARS.

It is the sales order number with an assembly plant, model year & model ID - not a partial VIN.

The first model year for partial VINs on the body happened later, for the 1969 model year. ;-)