Sunroof Seal: Should water be here?

[David Pfaltz]

First off, what a great forum! All of the questions I had I have been able to find by searching through the archieves. However, this one proves to be illusive. I have a 1989 190e that may or may not have a problem with the sunroof seal. After I wash the car or when it rains, water appears in the two black "water channels" (see picture for clarification) on either side of the roof and drains through the two front drain holes. I called the dealer and asked them, to which they responded that a little water was normal. According to them, it would need to be replaced if water was coming into the cabin--which to my knowledge it is not. However, isn't the purpose of a seal to keep water out? I guess I wouldn't make a big deal about this except for the fact that there are two small rust spots on either side of the sliding roof. I am assuming that this is due the presence of water. Any ideas? Thanks in advance.
David