It's listed below in Remington's 870 history section (you have to scroll down a bit). You'll see high-grade 870 Trap and Skeet guns from time-to-time at the bigger gunshows and high-end shops. They come out of the Custom Shop, of course, and they'll still build guns to your order.
I don't have a recent Blue Book, but it should
be in there. That will give you a good ballpark.