I don't think the body stamp #s will match the VIN# until 1969. The '68 body # will match the production # on the fender data tag.
If you're lucky enough to find a broadcast (build) sheet somewhere in the car, it will have the VIN and shipping order number on it along with all the option codes that should also match the fender tag.Exactly, the only place the VIN is located on a 68 is the tag. The other numbers will only match the original fender tag.