When we talk about 1911s that "old" Smith&Wesson is not that old. Any shots fired just makes it used. Find a dedicated S&W collector and you might get the high end of used or low end of used price.
So the $800-1200 estimate is pretty fair.
When you can still get essentially the same model new in the box, there's not much inventive to pay more for one just because its a few years older and sat in a safe.