Confusing, ain't it?
You're not the only one confused. I'm getting ready to change the plugs and am in the same boat.
I went to the dealer and asked what plug and gap to use. They referred me to the AC Delco 41-965 with a gap of .049. I asked about the 41-981 being used for the 02 and they didn't have any info for it. They just said it was for the 03 and later.
As tblazed says, AC Delco is showing both parts for the 02. However, I do not know that they are eliminating 41-965 for our vehicle. Also as he said, AC Delco has had different gaps listed on their site for the 41-965.
Edit: I'll probably end using the new plug 41-981 with .043 gap.