I Have A Question About Sleep. I've Read A Couple

I have a question about sleep. I've read a couple of places that REM sleep during daytime naps is abnormal and can be a sign of narcolepsy, since your circadian clock is supposed to keep you from dreaming during the day. Other places imply that REM sleep during daytime naps is normal as long as the nap is 90+ minutes and therefore actually gets to the normal REM stage of sleep. Which is it? If I'm having dreams during daytime sleep, should I be talking to my doctor about narcolepsy?