On the internet auction sites the older blue guns go for about 450 to 500. With a D 9xxx I'd say just keep it and use it. Those were good guns. Detonics really had its production line well de-bugged when that series was made. Shortly afterword they started using the new stainless steel molds for blue guns and had to go through a de-bugging process again.

Hope this helps, ...Deeton