Window rubbers for Z's can be had in two flavours - with or without chrome trim. Don either bought the wrong ones or didn't refit the chrome trim.
I remember from his original thread that he bought the aftermarket "Euro"/'Cal look' smooth rubbers, which do not have the OEM stainless trim sections.
So, decision to be made. Going with OEM style rubbers will require sourcing of the correct stainless trims (2+2 specific), whilst sticking with the aftermarket smooth rubbers will not.
The stainless channels probably help keep the rubbers in shape - especially around the corners -
but they were not vital for sealing. The car can tend to look a little '
something missing' without them though...