97 SC2 water leak damage

I am looking at a '97 SC2 that has a heavily stained headliner. The
sunroof is currently in a non-working condition. It seems to be the
entire headliner too, like it has done this for a while. I have seen
references to sunroof water leaks, and wonder if this consistent with
what others have seen regarding leaky sunroofs. I wouldn't be opposed
to sealing off the entire unit, if I knew that the sunroof was only
leaking through the area around the glass. I would appreciate hearing
from anyone that has experience with this problem.