These were very popular on British cars of the sixties - Cortinas and Hunters, for example - but I was surprised to see them on the 1977 Capri I had on test recently (see below). I thought they'd been phased out by then.
I've always thought this was a very simple and effective design but I recall reading somewhere that they tended to be leaky and draughty, and that's what eventually did for them.
Anyway, so keen was BMW to plunder the back catalogue of British car design for the retro detailing on the MINI that it reinvented the eyeball (see above for an example from last week's Clubman test car). I think the first BMW MINI had just two but the latest revamped version has four. Can't remember whether the 'proper Mini' had eyeballs back in the sixties, though.