If it helps at all, it appears the same switch was used on all three models (1500/2500/3500), by my '98 SM.
A bit of searching and the answer is: 97-01 (1500), 97-02 (2500/3500) all use the same power mirror switch. (This, of course, begs the questions as to how it moves from truck to truck and how it gets to my truck just when I need it. )