I know you have emailed us directly on this, Randy, but I thought other readers might be interested in the answer.
We only started making the 5.5 inch models when we got to the USA (we moved in March 1989). The Shadow IV that you have is the 32nd Shadow IV that we made and yes, it was made in 1990 - around October. There is some collector value to it simply because it is a numbered model, but I would not be too concerned about using it. It will stand up to hard work, and the beauty of these one piece knives is the ability to recondition. Losing the knife would probably be more of a concern!
The knife will have a little more value because of the number although that added value would only be important to a specific collector. There are others to whom it makes no difference at all! It is certainly identifiable if it were "liberated"!
Anne
