While your "books" may have goodwill recorded, the only time you have goodwill for tax is if it was purchased.
When you acquired your interest in 1996, and based on your facts you paid more than book value, the LLC should have made a Section 754 election along with a Section 743 adjustment at that time.
This adjustment, depending on the assets involved, would have been amortized over the years and specially allocated to you on your K-1.
Since there are a number of questions and unknown facts, I recommend you meet with a tax professional where you can have a one on one to straighten this out. You have a mess based on the limited facts, and the length of time that has passed is not in your favor.
*A reminder that posts in a forum such as this do not constitute tax advice.
Also keep in mind the date of replies, as tax law changes.
