Is windshield trim necessary?

So like many before, I have a 67 Dart with the lock strip style windshield gasket that just rained on me on the inside of the car on the way to work this morning. I normally don't drive it in the rain, but I didn't have much choice today. I'm planning to just buy a 68/9 gasket to replace the 67 style with so I don't have to worry about the lock strip, but I didn't really want to get the snap on trim. Is the stainless trim necessary by any means or is it just there to look nice? If the window just has a black surround from the gasket without trim that doesn't really bother me for the time being.

Every thread I found has people saying to just upgrade everything to the later 68/9 style, but they all talk about getting the clips and trim as well. As far as I can tell they are just cosmetic, but I wasn't sure if there was a really big gap or something with the trim removed that would fill with water or something like that. Does anyone have a picture with the trim removed so I could see what it looks like?