Just some general background. A bayonet on a Swiss rifle would be most reasonable. We see the Swiss as a neutral nation, non-militant but sensible on defense, but one may then ask, why then does the Pope employ the Swiss Guard as the Vatican's body guards?
The answer is simple. When first employed there as armed guards in the late 15th Century, the Swiss were known throughout Europe as not only the fiercest fighters, but also the most noble, dedicated, and honorable guards that could be hired. They would never sell out or retreat. You could count on them to "have you back" regardless of the immediate situation.
Go to Lucerne and seek out the statue of the Dying Lion of Lucerne. With a spear in his side he still charged forward, a symbol of the faithfulness of the Swiss Guard. There is a little park there today with falling water and a place to sit and contemplate it.
This is not the first rifle from the region that I have seen that was obviously made for hunting but was built with a bayonet attachment. Traditionally, the Swiss were taught to take care of themselves, and if pressed into service for national defense they were expected to come armed. Incidentally, we, too, had military Kentuckies, and an old friend of mine, Everett (Birdie) Partridge, may his soul rest in peace, had the finest collection of them probably ever assembled.
Incidentally, the Swiss Guard that you see today in the Vatican is largely ceremonial. The ones that you don't see dress in plain clothes and carry modern weapons. What, you expect the Pope to ride around with less security than a U.S. President?