Chief eventually started dropping it in 2002, this Japanese page has a nice timeline to it.
First capture in Jan 2002 references only Buryna dropping Eye of Rokgus:
http://web.archive.org/web/200201051.../cabnec11.html
A bit later in 2002 it is updated to say where you should go to get pops of Burynai for the eye:
http://web.archive.org/web/200204050.../cabnec11.html
Then in September 2002 it references Chief Rokgus dropping it:
http://web.archive.org/web/200209020.../cabnec11.html
But Chief didn't drop it originally. From the Allakhazam page, quest was broken until Eye of Rokgus was added to the Burynai around US Thanksgiving of 2000:
http://web.archive.org/web/200104192...html?quest=750