Found a few of my boxes. The factory thing actually is on some 1979 boxes.
Suzy Qs and Twinkies. But not on Big Wheels.
And some adds to the list all 1979
Suzy Qs 40,41,42
Big Wheels 91,92,93
97,98,99
More when I find some other boxes I'm pretty sure are around somewhere.
Steve B