where r the front seatbelt mounts 67cuda?

got the car shell, and a bunch of of boxes with parts. I've almost completed the restoration,up to the interior. I can't seem to figure out how to attach the front seatbelts (bucket seats). i know it should be obvious, but there are no holes where the frame would be,or even in the sheet metal. there are notches by the door rails,which may have had mounting hardware, i'm not sure. any feed back will be appreaciated. Thanks JT