Priced at retail from your description. Is it a Philly or a Utica gun? The early guns bring more than the later ones. What is the barrel legenth and choke? Does it suit your needs? Quality and fit did go down in the later years so date of manufature is nice to know.
These guns are not rare, so you can be selective and wait until one comes along that really grabs your eye. As a rough guide a eary gun might sell for $200-300 more than a later made gun. If it were a 20 it would have already been sold at that price.