Offer what YOU feel it is worth. It clearly has not been ridden in quite some time , so it will need to be disassembled , cleaned , greased , and reassembled , not to mention whatever consumables it will need . Right now , even as desirable as this bike is , the market is not good. The above estimate may be close , but who knows? The owner may just want to see it brought back to life and enjoyed. If it is your size and you like it go after it and offer what you can .If you are looking to "flip" bikes , that's a different situation. You may make a $100 or so but spend a lot of time and labor. This bike should go directly to the one who will enjoy it , IMHO. Joe