Taylor, sorry to hear of your father's passing. Your gun is from 1919 and would be an F grade hammer gun (rabbit ears) 12 gauge. These hammer guns were only sold through sporting good stores, hardware stores and likes. It would have Royal Steel barrels, not Damascus, and you had mentioned in very nice condition. Many of us here still shoot hammer guns using light loads, under 8,000 psi (pounds per square inch) and velocities under 1200 fps (feet per second).
As stated value is hard to determine without having gun in hand. This would be a nice gun to hand down to the next generation as these guns are getting harder to find in decent condition.
Good luck and if you need any other questions answered please feel free to inquire.