If the body was real solid I wouldn't think a thing of it. But if you already replaced the floor and wheel houses there may be something you didn't see, inside the rockers for instance. It may not be bad and you would never know painting and driving it. But the forces are pretty tough on those rockers on a rotisserie. Run a 1x1x1/8" bar at least across the door jamb. And I would make them so they clear the doors, just in case you want to install the doors while it's on the rotisserie. You may not think there is a reason, but I would recommend you simply spend a little time making those braces so you can do that.