"Canadian Guardsman Picnic" advertisement for Windsor Canadian Supreme Whisky (1978). Source.
I just ran across this ad from 1978 in an old Popular Mechanics. I was saved the trouble of scanning it for the blog because it was already online; incredibly, someone is selling this single-page ad for over USD$7 on ebay. The ad runs:
LOL."This Canadian has a reputation for smoothness. So you won't catch him drinking anything less than the smoothest whisky around. Windsor. A whisky made with glacier-fed spring water and aged in the clean, clear air of the Canadian Rockies."