Want-A-Vert

All, Im in the midst of a restoration on my 69 vert and the guy doing the body work says that the frame is a little twisted behind the axle where the trunk bolts down. He's saying 1/2" left to right and I wondered if this is common or not. I also wonder if it will be noticeable when its sitting on the ground. To put it on a frame machine is 150 dollars, but the car has to come back off the frame, and I dont feel like doing that agian. Advice? Exeperience? Opinions? I would just hate to get it straightened only to find out its the way the car was sitting because it is a convertible and very flexible.