I mean this photo.
All I can find, everywhere online, is that it was “from 1976.” No indication as to which month in 1976. Anyone have better google-fu? (Or one of those scary basements full of every LIFE magazine and National Geographic?)
It wasn’t Time magazine?
The information I can find indicates that the photo in question was from a photo shoot for a poster company. That’s not to say it might not have been in a magazine as well, but that would have been after the initial use.
From the Wiki img link:
From People:
That same passage seems to be cut-and-pasted into zillions of stories following her death (mentioning “published in Life magazine” and “12 million copies sold”). So that could also mean that it’s internet crap that spread widely despite it being incorrect.
Yes, it was a poster that was very well known. Steve Martin once complained that she wouldn’t answer any of his letters, “after all those hours I’ve spent holding up her poster with one hand.”
I never had one, but I had friends who did, and I saw it in the stores.
Between January 1973 and September '78, Life magazine didn’t exist as a regular publication. During that time it was only published in the form of one or two special issues a year. An overview of the contents of those special issues can be found here.
I’m sure the wiki about it appearing in Life magazine is erroneous. The backstory is that it was taken at a photo shoot specifically for a poster.
http://content.time.com/time/arts/article/0,8599,1907185,00.html
It’s doubtful that the same pic would be given away in a magazine the same year.
What makes the claim even more suspicious is that it happened in 1976. Life went out of print in '72 and came back in '78. 
ETA: What journeyman_southpaw said
I would think we could narrow it down to one of the winter months.
The link in journeyman_southpaw post shows an issue in 1976 “Remarkable American Women” … [sigh] … Farrah didn’t make the cut apparently …
Nothing in that article at all about the picture being taken for LIFE(or any other) magazine. he was contracted to shoot her for the poster, and that’s what he did.
Bear in mind that the poster was enormously popular and was reprinted in magazines. It would not surprise me if Life were one of the magazines; in fact, it would seem an obvious choice for Life (although of course it would have to fit in one of the few special editions that Life published in 1976).
Yes, I remember the poster was ubiquitous. I don’t think there was an American who wasn’t aware of it in 1976. I even had a jigsaw puzzle of that poster. It sure was fun putting it together. 
It hung in my bedroom right next to my Dallas Cowboy cheerleader poster where we we got high listening to “Frampton Comes Alive!”. If the walls of that room could talk I’d have to kill them.