Black spots on ceiling = leak?

Thanks for the replies! Right after I posted I remembered I hadn't even tried to wipe them off. Just went out and tried with a wet, soapy paper towel. Some came off, some didn't. The ones that didn't appear to be in a shallow indentation in the ceiling. I'll try later with a toothbrush.

My camper is outside in the central CA coast winter and closed most of the time, so mold sounds very possible. Only see it on the ceiling, though.

I agree with the frequent inspection goal, but can't talk the old body into it always. :)

Thanks again,
Ralph