Thank you for your reply.

I did not see the 126 sunroof, but I saw 123 sunroof. The sides had felt.
But in 124, sides are also rubber.

I touched up a rust area with POR-15 where the rubber meet the roof body. And then applied white MB touch up stick above POR-15 coating. It was a few months ago.

The area with MB touch up paint makes me worry.
The area that faces the sky looks OK. But the small area that faces the rubber has dark dots because the white touch up paint was removed partially.
I hope it is not due to rust growing beneath the POR-15 coating.