While I would never stoop to stereotyping Gord’s fans by virtue of their vintage I think many ,(including his US fans) can run their memories as far back as 1972.
A wonderful Irish gent ,”Gilbert O’Sullivan"’s biggest hit around the world :
US BILLBOARD SINGLES CHART
DATE OF CHART ENTRY TITLE HIGHEST POSITION WEEKS ON CHART
17 June 1972 Alone Again (Naturally) 1 18
The start of verse 2 goes like this :
To think that only yesterday
I was cheerful, bright and gay
The use of the word in that context was unusual but not unheard of (certainly in the UK anyway) . While the song is about a bloke getting stood up at the altar I am pretty sure it was not implied that this was because of his self confessed gender preferences.
As a kid I was fed a diet of older musicals by my Dad including one called “Salad Days” . One of the (IMO) better songs is called “We’re Looking For a Piano”. The musical centred around a magical piano that had the power to make people (involuntarily) dance.
https://www.youtube.com/watch?v=3KH08D2gQ1s
Buried away in the song is to the best of my recollection (something like )
“We’re looking For a Piano ,
Not any old Piano
It’s one that makes you gay “
(Oh confirmed and just found the line at about 2:10 in the embedded You Tube sound bite / clip.)
This musical was written much earlier but the pattern and useage was in the same context.
cheers
One of your old Aussie "gay" mates.