"Chicks dig it" is not a legitimate use of a firearm, as is covered in any basic firearm safety course. However, defending oneself from the Inevitable Zombie Apocalypse goes to the very heart of the Second Amendment.
Off topic, but man, it is a wonder we survived in those days. Can you imagine trying to repel zombies with a muzzleloader that takes 30 seconds between shots? Even with a bayonet on the end, that would suck.
Actually, the bayonet is probably more useful than even modern firearm. A good broadsword and plate or mail armor + shield would be even better still.
Some of them would likely have access to guns, but they'd probably still lack the fine motor skills required to aim and fire.
And in those days, the population was a LOT smaller--and largely pastoral. So you don't have the huge zombie hordes you have nowadays.
You'd think that.... Swords and plate or mail armor and shield gets very heavy very fast. Even for men in the best of shape.
I'm ashamed to admit that I don't know if you can zombify a horse. I've never seen it happen, so maybe only higher primates can be infected. Anyway, the point is, the only way to be able to function effectively in medieval armor is on a horse. On foot you'd be quickly overwhelmed and taken apart like a lobster.
I find that some of the research done in that series may be intentionally misleading to sensationalize the threat. For a more balanced and fact based source I refer to World War Z by the renowned historian Max Brooks.