Poly Paks was around for a long time before 1976. They seemed to specialize in rejected components. I think I still have some LEDs that I got from them - the two leads are the same length and they are aligned parallel to the flat part of the base instead of perpendicular to it. They also sold me some resistors where the color red was indistinguishable from brown. The LEDs and the resistors worked OK, once you figured them out.
Don