$1000 to $1200 seems about right, but more importantly what is the person asking and what do you think you can get it for? Tank's bad, exhaust is shot, chrome is shot, carbs are likely gummed up too. Clean title? Mileage?
They're fantastic bikes, and that looks to be in decent shape with the faults already listed aside.
Decent tanks are going to be around $150-200, more for better shape. Knock-off 4-4 exhaust will set you back $1k for a new set, people don't sell them used it seems. 4-1 set will set you back $350 or so, more for better, or you could run 400F pegs, brake lever, shifter linkage and pipes.
You'll also likely be looking at some more maintenance like rebuilding the front brake, going over the rear brake, etc.