A factory rib would add value. Is is a plain barrel, a solid rib, or a vent rib. A retrofit vent rib would bring value to somewhat less than a plain barrel original. Is a grade marked on the bottom of the receiver, like "Skeet" or "TC"? That also would add value. Yes, a field choked gun could be a "Skeet Grade". And, yes, a 28" barrel could be installed special order on a TC Trap Grade gun.