Modern seats and shoulder belts

Can someone show their upper mounts? My 67 Barracuda has lap belts only with no upper mounts showing. I had a '76 duster years ago with 3 point belts so I have an idea where they should be. If I don't have a upper mount showing how do find out if there is a mounting point under the headliner. Do I have to cut the headliner to install one?