Vin issue 1965 barracuda

I bought this car last night as a parts car for another 65 we're building. Of course I want to check out the vin and be sure I'm not cutting up a decent car. The motor checks out correct, which is why i bought the car, but the vin is a big question mark. The vin plate doesn't appear to have been altered but nothing matches up. It has the stripes like an S car, one of the knuckle assemblies on the front end have the sway bar part. But the rear valance doesn't have an exhaust cut out. It's a 273 2bbl, auto floor shift car. I hoping one of you knowledgeable folks would take a look at the numbers and give me your expert opinion. The vin says: S20003KAN, the motor A 273 12-11, and the core support number is 7C1200133? Thank you in advance!

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The “A” prefix stamped on the engine indicates that it is from a 65, most likely the original engine from the car. If there’s a fender tag, a Formula S car would have the digits “31” under the “ab”, indicating a 4 barrel engine.