That I can believe, when I built truck bodies sometimes we'd have to move them after tacking the body together. Driving slowly around in a 17 tonner with only a couple of tacks at each corner holding it all together we never had one fail even though the body would twist and move as you went along the bumpy road around the factory.I wouldn’t be surprised if you calculated the minimum amount of welding required to support that weight on that design is no more than 6 hot tacks.