Where on the 1965 Cadillac Coup DeVille can I find it?

I don't know, but I like a '74 Coup De Ville better.

Either on the dash,drivers side,seen through the windshield, or on the driver's door, on a piece of metal, riveted on. Or your local Gestapo can tell you,( if not the highway patrol fur shur!)

You will find it under the hood, on the driver side firewall, or on top of the cowl(underhood)

the VIN # is located in two places the easiest place to check is on the drivers side dash right where the windshield meets the dash there is a small piece of metal riveted to the dash that has the Vin stamped on the little piece of metal. The other place is located on the driver's side door there should be a piece of metal riveted to the door jamb with the year Vin and color codes and interior codes.Reno

look on the bottom of the wind shield of on the front of the dashboard

In the 60's GM put the info you're seeking on a tag riveted to the driver's door panel. If it's missing then check under the hood for something known as the cowl tag. It will have almost all the info about the car on it. If it's missing then take back seat out and hope the build sheet is there and nobyd has already removed it too. There will NOT be a tag at the base of the windshield like there is on newer cars.