exactly what is the locking strip on a 67 dart windshield

RedFish said
The insert spreads to in effect lock the gasket. Remove the insert. OEM rubber gasket and the sealant that was used is probably brick hard today. The glass still may not pop out easily.
In my experience, a 50 year old windshield is cloudy and pitted to hell too so breaking it is a good thing.

this is a new windshield and gasket used some joy and popped it right out needed to put the 67 dash frame in and get the lm23p out now this is a righteous 67 with title and vin matching now too put the windshield back in hope its as easy had someone helping that knew how to do it