It was when Spurrier was brought in to Head Coach. My cousin managed the retail store in the stadium and the merch was very black accented. He was told they were considering changing the jerseys the following year. I have a stadium parka, I worked game day, from that era somewhere.
Looks like after buying Reebok for all the sports contracts and killing the brand to the point where you can get Reebok shirts at Walmart, Adidas is finally wanting to sell the brand: https://morningchalkup.com/2020/10/26/adidas-prepares-to-sell-reebok/