Verg, the class 10 slot is the slot used with prototype weaponry and nomad weaponry. All normal guns are at their best, level 9s. So technically, speaking from the average citizens/pirates/military point-of-view, level 9 is the best of the best. So normal guns shouldn't be made level 10.
Also, if there were actual weapon limitation on fighters, than nomads and codenames would be reserved for a very few people. Basically, the codenames would be for BHG, RM, Outcasts, GMG, and Corsairs only, as the codenames in existence were made by them. Nomad weapons would be for those who are nomads or who operate around the nomad's area. Also for the BAF, BP, and whoever owns Cambridge Research Station, as CRI makes Nomad weaps compatible with human ships. That means those three plus Corsairs, Zoners, Outcasts, and Bounty Hunters only.