Thank you! Clear now!
I found this kind of pictures, so with yours I have what I need.
What I was after mainly was gluing of the rear seal - so glue it is. Thanks, I thought I might have been missing some rail or tabs or clips.... but it is glued.
The front one I bought from MB - it fits ok, not so easy to tear it away. You just have to manage length as you go - you are stretching it when pushing into the slot, so you need to compress/slide it back otherwise it is too long.
When I tried to order the rear seal from MB, it was EUR 450. I decided to order it. But when it came, it was already almost EUR 1000. I did not take it, I wrote a complaint - on price being different when ordered and when delivered.
I bought one from SLS.