depends on how good of a job they do on the replacement and repaint and blending the paint. Any sort of collision repair, paintwork, etc, is typically a bargaining point... I'd say a perfect repair job should still be pretty close to the pre-accident price. If it's obvious that repairs were done, subtract accordingly.
If you're serious about the car, I'd still get it inspected, there is a rear subframe and also the suspension points among other things that should be checked out as well.