1970 challenger 340 6 pack TA

Looks like some rust around the back glass to me where the vinyl top meets the glass on the RT side. You might want to double check the rear floor and trunk floor for rust damage.
Yes the T/A had a special suspension. It should also have the T/A steering box. Some cases cars did not have them, but most should. Alaskan T/A should be able to answer all of your question concerning these cars as he is very knowledgeable.
Good luck and keep us posted.
Matt