That's pretty interesting. Considering Infiltration version 1 was only released in May of 1999, I'd say playing it for the last six years is nigh impossible, unless you beta tested an early early version in january of 1998. Unfortunately, since unreal didn't even go gold until May of 1998, I'd say your claim is impossible. As to swaping the menu music, why bother? The menu music is exactly the same between 2.86 and 2.9. Exactly the same. No changes whatsoever. Only the menu itself changed. Maybe you're thinking of the much much older version, Infiltration 2.85.
In addition, if the Infiltration team had meant the eight ball to be a real weapon for use, they wouldn't have required a mutator to make it work. They didn't have it in the armory. What would make you think they were serious about it? The eight ball was expicitly made as an exmaple to others on how to implement their own weapons in the game, nothing more. Get over it.