Yep, a gun is worth what you can get for it. Sometimes that's retail, sometimes that's wholesale and sometimes it's cash over the tailgate of a pickup truck. It all depends on how fast you need the cash and how dedicated you are to finding the buyer who will give you top-dollar.
I know that doesn't answer your question, but it's the best answer I can give you. In some parts of the country it might be more, in other parts of the country it might be less. It simply depends on what the buyer is willing to pay.
However, if you want a numeric figure, the best place to look is one of the online auction houses like GunsAmerica or Gunbroker. You can see what number other folks are putting on the same model as the one you have.