Vent window 67-9 cuda

Things are good here, hope the same for you!
There is a plastic moulded/flicked piece that is brittle as hell and I'm not sure who repops them. It fits vertically on the leading edge of the door glass and slides inside the long support.
Take a flip thru here, it's about converting 67 doors to 69 but the piece were talking about is the same for all 3 years.
It's a dang wrestling match! I had the door flat to work on it.
Hope that helps.
67-9 cuda door repair questions