I don't have numbers in mind, but I will say two things. First, commemoratives in general are often not worth as much as one might think because the appeal can be somewhat limited as they are indeed marked differently from the main stream models. That said, I suggest not selling it too quickly to an early offer without indeed getting enough information to make you very comfortable with the value being placed. JMO
BTW I did see your post on the old thread on the subject.