I can't confirm the 757s, but I do recall that we got some 737 Classics from a European airline back inthe late 90s that didn't have the eyeball vents (I want to say the company was called Germania). Like anything else in the cabin, it's all optional and you can set it up however you'd like. This particular airline operated in relatively cool climates and decided they didn't want to pay for all the extra ducting. I seem to remember that once we started operating them in the deep south, they were tough to keep cool in the summer.