No access to Gun "Blue Book" - dad is selling off his stuff. At age 85, with Alzheimer's taking its grip now .... well.

He has a Remington 11-48 in 28 Ga. This is a field grade, nothing special at all, shotgun. Wear looks normal to me. I disassembeled and cleaned it up. I doid not find anything wrong with the gun.I then shot 10 rounds to check it cycling. Did fine. Then cleaned again. Any idea of the value? He was thinking about asking $200 - $225.