Hey, I'm just an ATCer, but my best friend's a Delta pilot. When I asked him this very question some years ago, he said, "when I put out my elbow it hits a window in a 75. It doesn't hit a window in a 76."

Of course, he lies.

Dave

767 Centre fuel scavange , 757 none
767 Flap 1 leading edge slats only, 757 Flaps 1 leading edge + trailing edge flaps

TOM 762's
 

Know that AA AB IF and IG were all had electronic door opening / closing