Am I at greater risk of developing narcolepsy if I test positive for two copies of the HLA-DQB1*06:02 allele versus one copy?

Yes, homozygotes (who carry two copies of the HLA-DQB1*06:02 allele) have a 2- to 5-fold increased risk of narcolepsy compared to heterozygotes (who carry only one copy of the HLA-DQB1*06:02 allele).