There is more than one glass "Nu-Ray" lens out there, just as an FYI item. The one pictured here in this thread is the Tiger Eye version that has more of a cylindrical shape to it. The other version is the Nu-Ray Junior lens that was used on Cushmans and a handful of other motorbikes and scooters. The Nu-Ray Junior lens is a glass dome shape but not pointed or bee-hive. The Nu-Ray lenses were made by the Do-Ray Lamp Company so they can be referred to as such or as Nu-Ray.
I like the glass lens look much better than plastic, though I personally go for correctness over style. Unfortunately I have no information on glass/plastic transition at Simplex.