I assume you're looking at the greyish race department sticker that's on the front of the plate.
My understanding (there are others around here who can chime in with better info):
Higher number = more flexible, lower = stiffer.
The first number is the tip, the second is the tail.
Sort of typical numbers -
Full-on race stock slalom: 37 / 26 for men, 41 / 29 for women
Retail slalom with race dept sticker: 47 / 36
GS: ranging from about 47 / 37 to about 53 / 42