Getting back to the topic, I finally found one of the web pages that talks about the demo knife pin punch. Shazam! It was bookmarked in my favorites list. Here is a quote from the page and a link to the forum discussion for further comments on the demo knife.
Another feature on the knives made between 1944 and 1972 is a serrated stud projecting from the side of the screwdriver/cap lifter blade.
For years nobody, including most of the manufactures, knew exactly what it was for.
Finally, some obscure WWII document was found in the Camillus factory archives stating the stud was
To Assist in Taking Down Small Arms.
It turns out the serrated non-slip stud is perfect for prying the extractor off an 03 Springfield bolt, punching the pins out of a 1911 pistol, M1 Garand, or M1 Carbine trigger group, holding down the stock band retainer spring on M-1 Carbines and 03 Springfields, and a host of other uses, on a host of other weapons of the time.
Some unknown designer really did his homework on that little feature right there!
Anyway, the handy dandy pin-punch was eliminated on the 1972 contract, and never seen again.
http://www.thehighroad.org/archive/index.php/t-684950.html