Earliest listing of this quest was on March 21 2001:
https://web.archive.org/web/20010321...tml?quest=1210
That's about 3 months after Velious launched, and it lists the BFG as the reward.
The only thing that seems strange to me is that the quest text DOES say that he has "plunder and booty" to part with as a reward. However, he gives you an item named after himself so it seems more personal than "plunder and booty." But Verant was never known for consistency.