Found your article really informative. I’m with you that the Happy Face was around prior to the early 1970s. I bought an “original” Happy Face mug for my grandmother when I was on a school trip, and I’m pretty sure it was prior to 1970. That mug is now a pen holder on my office desk.
(ahem) Long life the smiley/ happy face! 
Is this the column you are referring to?
In the late 1880’s (if not earlier) teleprinter operators signed off with a smiling face which was : o ) without the spaces and if you looked at that sideways it shows eyes, nose and smile.
Interesting piece of investigation and lore.
Thanks for the lookback.
That’s an emoticon. I’ve never seen that particular story in my occasional research into the history of the emoticon. Do you have a cite for it?
The Wiki article on the smiley or happy face: Smiley - Wikipedia
Previous threads on the topic:
In 1936, the Rockford (IL) streetcar system folded. The streetcars would be replaced by buses.
The local yahoos thought it would be great fun to celebrate this event with a bonfire. Accordingly, a single streetcar was brought to a main intersection in the city and burned.
The book “The Rockford and Interurban Railway” (Electric Railway Historical Society, 1956) had a picture of the “before” of this fine event. The streetcar was adorned with a banner expressing joy and a big, circular, smiley face. It was very similar to the smiley we all know and hate, but as it was a B&W photo, I couldn’t tell if it had the infamous yellow background. I remember feeling a little astonished to see that picture, as I too had thought the smiley a product of the 70s.
If the face is dark grey, nearly black or black, it wasn’t yellow. The lighter the grey, the more likely it was bright yellow — unless it was white.