I confess that this might have come from later than the 70s, but looking at it that doesn't seem very likely. Those "drinkups"...
Thanks to Dog & Hat for the tip-off! They're here: https://geni.us/dogandhat
Note: I have no affiliations with them, just they DM'd be on Instagram.

Links:

Patreon:   / jameshoffmann  
My Book: http://geni.us/atlasofcoffee
Limited Edition Merch: https://www.tenshundredsthousands.com
Instagram:   / jimseven  
Twitter:   / jimseven  
My glasses: http://bit.ly/boldlondon
My hair product of choice: https://geni.us/forthehair
My coffee kit (studio): https://kit.co/jimseven/studio-coffee...
My video kit: https://kit.co/jimseven/video-making-...
Neewer Products I Use:
https://geni.us/neewer-C-stand
https://geni.us/neewersl60
https://geni.us/neewerslider