[Alex van de Wetering]

Jacek,

The parts manual (C8) does mention "weatherstrip, windshield frame support to roof angle". C01Q 811169 / 1798724, which I think is what you show on your picture.....although I think someone might have replaced the weatherstrip with some black sealant or glue to keep the water out of the cab??

I have to check the remains of the wood support of my roof to see if there is any trace of those large holes on mine, but I can't remember I have seen these. I can't find any reference in the manual for any big washers or something.

One of my seats it also missing that locking mechanism, so can't help you with that. However if anyone has two to spare....

Alex