I picked up a bayonet last weekend. The only stampings include "US" and the year "1900", the same year when this article was written.
BR, I can't tell if you have some discoloration in your beard or if you are drooling. You do look like you belong there, except your Stormy Kromer hat didn't come out until 1903, missed it by just a few years. Otherwise you could fool a lot of people.  ;)