Ah yes, I forgot about that scene. I guess I was thinking they were for low light settings, cuz well, that's what the decal says on mine, lol - "avoid using in brightly lit environments or severe eye damage may result." I'm not sure if someone just made that up, or GB2 forgot about it, or maybe those are 'improved' goggles, or what... Surely though there's some unique feature to these ecto-helmets. We just gotta figure it out!
I think it's pretty unlikely the RGB filmmakers just forgot about the ecto goggles - they're a notable part of GB1, and appear in earlier episodes. The helmets must've been created by this episode's script writer, if not earlier (and maybe the script would explain more about them if we could get it), and had accompanying blueprints. I don't reckon individual animators would've been given that much creative leeway to invent whole new gadgets.