IMO - it's worth whatever a Benelli SBE3 in 20 gauge is worth.
The Ducks Unlimited aspect really doesn't play too often due to the fact that usually - any DU chapter in the country could order one for a benefit. Meaning - there's a lot of them out there and they're basically a SBE with window dressing. Nothing super special done to them mechanically.
Been a long time since I was on a chapter committee but IIRC, when we ordered guns, the price was the same DU or non DU edition for our benefits.