The Great White Brick - '69 Valiant
No, the car was sitting on jackstands, positioned at the front of the rocker, just ahead of where the crossmember is located, and at the rear on the rear frame. Here's a couple of photos showing the front jackstands.
The sill gets welded along the bottom to the outer rocker and along the top to the door frame I guess you could call it. If all this is missing on your car, I think your car might be too far gone to fix. You need a certain amount of metal to be intact, know what I mean?