I just removed the rubber bushings from the front suspension of a 75 that was sitting for a long time.
The rears were very squished and thin in one area and it appears that the torsion bars had worn from contact with the control arms.
Question, is this just from old worn bushings or a sign of something worse?
Do the torsion bars need to be replaced?
Thanks for any information you may be able to provide.

Yes, your bushings are worn out. Pictures are required to diagnose better. Minor rubbing on torsion bars is not critical UNLESS slots are rubbed into them.

start with new bushings then address the bar good luck

I had the same issue years ago and did not replace the torsion bars, and as few months later I woke in the morning to find one side of the front end sagging. The torsion bar had snapped while sitting in the driveway. I could not imagine what would have happened if that had happened at 80 MPH.

If the integrity of the torsion bar has been compromised, I would replace it, or keep it under 45 MPH.

I can hook a fingernail where it is worn so I am guessing replace.

Must replace the bushings but if the torsion bar is not very pitted, you can polish out the scratches and re-finish. Many years ago I had a fractured torsion bar due to corrosion pits that led to fatigue fracture. My current project had some wear but i was able to polish them smooth. Fatigue likes to start as pits or surface sharp indentions. If removed leaving a smooth well radiused surface, should be OK.