just enjoy your car and quit fretting!
over the years I've seen original hemi cars the factory forgot the torque boxes,factory made typos on the tags, but either no build sheet back into the car or they stuffed sheets for 5-6 cars in that one car, etc.
details will vary by the plant that built the car. yes, radiator support and under the trunk lip weatherstrip is likely place to look for vin. like they said, very few will still have the # matching engine or trans, but they both will have the vin stamped on them ( starting 69 if I remember), no vin means warranty block.
also remember, Mopar was very good about building a car "your way" back then. black roadrunner with blue int. had one, not a factory offered combo, but they built it that way for that customer. just an e xample.