[sigh] One laments the day when gentlemen knew the etiquette of duelling.
Bespokekiwi should not bring a pistol. That is a job for the seconds. And two pistols would be required. But, as you are proposing the contest, choice of weapons is actually up to the respondent.*
* I made that last bit up. But it sounds right.
One notes that Claghorn is originally from Texas, a place which invents its own etiquette, or ignores such niceties entirely. Besides, no matter how bespoke the kiwi, it is a well-known fact that ratite birds are terrible shots, as one would expect, having no upper appendages of any sort.