You really need to look at behind the glove box to see if you have the little door that opens to insert them. I recall seeing a picture on here once of some that don't have the opening. In that case, I believe you can cut the housing and make the door for the filters, as the housing is the same design otherwise.
My '00 had the door, but no filters, so I just bought a set and dropped them in. Do they do anything in particular? I can't tell, but I definitely don't have leaves blowing at me.