I suspect that its not a saw back, but a fish scaler. I've seen other folding fish knives with a scaler on the back of the blade or even a second blade with that pattern.
Originally, this pattern was produced by Schrade as "George Schrade's Stainless Steel Hunting and Fishing Knife" in the '20s and '30s when stainless on knives was a really novel thing. In the '70s or '80s, it was copied, and made in Japan as your Cousin Willie knife. And I have neither yet. Have been meaning to pick up the original Schrade for some time.