I edited down the spdat files from my Classic/Kunark discs to compare to the alt.games post.
This first link compares the 2-16-99 spdat referenced earlier in the thread to the 5-20-99 post.
Mostly seems like stuff that just wasn't ready when discs were printed.
The second compares 5-20-99 to a 3-14-00 spdat from the Kunark disc.
Some more interesting differences to be seen here. Of course Clarity/Insight, but also Berserker Spirit in place of Soul Bond, which reads like it was another tier of Alliance/Collab. Shrink, Bonds of Force, ResurrectionEffects?? all seem to be after May 99.
I didn't start playing until early 2000, so maybe some of these things are well known. Anyway, I can't wait for Green!