I was just looking/hoping for a little more reasoning as to why they would use the name of that race for their cover story. Humans and Vulcans don't look that much like K'normians.
Neither do Bajorans. There's no law that says a person of one species can't buy or operate a ship built by a different species. Heck, we've seen plenty of instances in the shows where the same starship model was recycled for different aliens' ships, like the Arkonian warship from ENT: "Dawn" being reused for Xindi and Tellarite ships later. So there's precedent for the idea of one species buying ships built by a different species.
Yeah, but in the film Kirk says to the security guys that "you're K'normian merchants now". To me, that implied that they were supposed to be pretending to be from that race.
But I guess he could have just meant "merchants for the K'Normians". Which, as you say Christopher, could be from any race.