The red post coupe that I purchased back in 2003 at a cost of $2,000 has a good frame, with only a small hole on the left side that was easily repaired. The body sheet metal was severely rotted, but the SS trim and running 401 motor & 300 trans was all there. Sourcing all the rust free sheet metal parts took years. I preformed all the mechanical upgrades & welding needed. I also purchased another post coupe just for the door and side panels ! All the rest of the interior parts were purchased new from OPGI and other vendors. Without finished bodywork and paint the total cost was aprox.$18,500 when it returns from the body shop the cost will be around $30,500 and this is not the rare manual shift GS.
The $2,500 they are asking seems a little high for the GS considering that you will have to find so many of the parts to bring it back to stock, If that's what your goal is.
It looks like more of a parts car from the photos you posted.
Tony