Generally most sleep labs can accommodate Night, Day , or Evening sleepers. Just be sure and talk with your PCP and Sleep lab staff when setting up for your sleep study. Since you have Narcolepsy they may wish to hold you over for an additional exam- MSLT (nap test) so be prepared to stay an additional amount of time
When you have your lab consult ask lots of questions and discuss any special needs for your sleep exam, including the time of day that you prefer to sleep.