Primarily Petroliana Shop Talk Forums Thread Like Summary - Milkglass Shell clamshell first appear on pumps?

First post...I did search but did not find the answer. Does anyone know about when the milkglass Shell clamshell globes first appeared? I realize that once out, they could have been stuck on just about any pump, but I was hoping someone has some evidence of what years/generation of pumps they first appeared on. My motivation is that I have visions of finding a pre-visible and adding the clamshell to it. I can use Photoshop to see how it would look, but if they likely never appeared that way, I might think twice.

Thanks in advance.

It may not be period correct, but since you can still make out the Shell emblem on the lower skin, I like it.

first thing that comes too mind is foreign ? .. ...