[K code Mustang]

My buddy just bought a 68 Cutlass S that is believed to be a Ram Rod car. I read there were only 679 produced, but I really don't know much about Oldsmobiles...can anyone give me any tips on where to look for verification. The car has a four speed and 391 rear, but it is missing the original air cleaner and exhaust manifolds. I will try to get some pictures up as soon as I can. Thanks guys.