Yeah, Lefty, I'm not sure how old the song was when I first heard it. It might date back into the 40s or even earlier. All I know for sure is that it enjoyed a lot of radio airplay during my early childhood (born 1947), whether it was brand new at the time or already a Christmas "oldie."

I did some research on "I Saw Mommy..." a few years ago, when I was working as a shopping mall Santa and had begun playing the tune on my toy xylophone as a way to drum up business. I don't remember the details, but I'm pretty sure that it's yet another post-WWII phenomemon, from the time when the first baby boomers were babies (late 40s/early 50s).