Gerry:
If you are looking for a educated opinion on value you will need to post pictures.

I have seen the Model 700 Webley & Scott 20's for $4,000 to $6,900 depending on condition. The $6,900 was for a NIB gun. I don't know how the Orvis guns compared to the Model 700. I don't think W&S has made the Orvis guns since the 60's or so and I think that era was better than the later W&S 700's.