Ah, I found the "transom" version in the Unofficial College Songbook website, which appears to come from the University of Wisconsin in the 1950's. The Website, drinking songs.net, looks very much like John Mehlberg's im mort alia.com

HER MOTHER NEVER TOLD HER

'Twas a cold winter's evening,
The guests were all leaving,
O'Leary was closing the bar,
When he turned and he said to the lady in red,
"Get out! You can't stay where you are,"

Oh, she wept a big tear
In her bucket of beer
As she thought of the cold night ahead;
When a gentleman handsome
Peered over the transom
and this is the story he said:

"Her mother never told her
The things a young girl should know
About the ways of college men
And how they come and go.
Age has stolen her beauty,
Sin has left its scar.
Remember your sisters and mothers, boys,
Let Nelly sleep under the bar."