2004 Lesabre. Air ride shocks recently replaced. Recently hit in the right rear. Only $1K in damage (bumper cover, tail light). Got them to toss in a 4 wheel alignment. Car is at the shop now.

SOURCE: 2004 Huyndai Santa Fe - Negative camber on rear passenger side

It is possible for the chassis to sag, but this is far more common with much larger, heavier vehicles. Likely, you have something in the suspension that is bent or mount bushings that are worn oblong where the center bolt passes through. A good shop can find this after a careful examination. subtle bends are difficult to detect...parts have factory bends in them and unless removed and matched up side by side with a known good part, you would never see the difference. Bending does not always involve an accident. A sideways slide into a curb in snow or even a decent pothole at the right angle can cause a bend. Likely it is not unsafe but it will wear your tires.

SOURCE: Negative rear right camber

If you bought this vehicle second hand then you need to get your vehicle checked for crash damage. Your insurer can do a check on a vehicle register for a small cost, but that is only if the vehicle was damaged AND repaired/written off via an insurer. this does not guarantee that the vehicle has never been in an accident, you need to look underneath to see if there are any kinks, tears or ripples that don't look quite right. But I would advise taking to a professional repair shop for a good look over.
If the bolt has been replaced, and the readings are correct, then you should be safe enough, just drive steady. But if you are suspect of this vehicle get it checked .

SOURCE: how can I repair my sagging rear bumper on my 2005

go to a friend or a bodyshop. get a bumper adjuster. it has a 3 to 4 foot handle on it, with a hook on the other end. you can easly bend a bumper where you want it...