Interior-Making the assessment
Most interior items ca be looked at visual and it can be determined at that time to either replace or repair. Get your notebook out.
Open the door and look at the door panels. Do they have holes for speakers? Does the bottom of the panel attach to the door? Is the window rubber still in good shape? Are the armrest, door handles and window cranks in good shape? On the premium(mostly muscle Gran Prix and Trans Am’s) cars, does the electric windows work? How does the chrome look on all pieces?
Dash and Console-If this is a running car, does the electric system work? Check each item. Look for loose wires under the dash with Flashlight. Has the dash been cut for a modern radio? Did someone hang gauges or CB radio from the bottom of the dash, leaving holes that will need patching? Doe the heater and AC controls actually work? They may move, but unlike modern cars the doors are controlled by cables. The cables may move, but the door may not operate correctly. When opening the glove box, does it have the correct interior box and does the light work? Does the steering column and all of its parts look as they should and work properly.
If equipped with a console, Check for holes that were used to mount gauges or CB radio toward the front. Box and lid need to work properly. Light should work on shift indicator. On older models the wood grain look should not be peeling off. Does the shifter work properly.
Seats and Carpet-Look for wear and tear in the area of the bead that separates the middle design from the plain section on the outside. Look at the chrome and plastic piece that goes on the bottom of the seats. Check function of the seat, does it move forward and back, does it move forward when the button is pushed. Some premium seats had a recline function. Is the carpet the correct color, does it have major wear around pedals or heal areas. Does the brake and gas pedals have the correct cover and trim?
Headliner-is it attached to all of the ribs correctly? Any tears or does it flop when the windows are open?
Rear Door Panels-do they have the correct ashtray, is the chrome in good shape? Has someone cut holes for speakers? Door molding is attached not loose.
This is just a first visual list, as when the dash and carpet come out the rest of the story gets told. You can make a full assessment of all of the work that will need to be done.