Hopefully they're all the same number.
On the 1964, the serial number is on a plate inside the door. it is also stamped on the crossmember by the
radiator, and on the metal underneath the (removable) cowl. I would guess that the 1965-66 would be the same, but don't know. Newer cars have the VIN number in more places.
True story: a friend of mine has a stolen car. It is a 1968 Dodge Charger. Somebody in Massachusetts (I think) bought the car new, and a short time later the car was stolen. It was reported, and after a period of time the insurance company bought him a new car. The crook kept the car, eventually replacing the grille and trim to make it look like a 69, and used it for many years. It became old and collectible, and he took it to local car shows. One day he moved to Kansas. When he tried to register the car, they raised an eyebrow over a phony VIN number. They checked in other places and did a
search -- found the car reported stolen. One day the original owner got a phone call from the police -- surprise surprise! He no longer needed or wanted the car, so he sold it to my friend.
