Bonzo,
WP did offer a upgrade for the 43's WP's but it was mostly a waste of time. The changes where more techincal in nature and not very benifical. (I'm not sure if your 01 GG forks would have them stock or not.) Depends on when they where manufactured.
The best bet if your looking for improvements is to find a reputable tuner and have them dialed in for you.
The part # was R509. It runs about 150 bucks. The 02 and up forks had it stock. From what I've heard it was a different comp&reb tap.....used bigger orfices.....more free-bleed at the same clicker setting.