Yeah this updating has been omitted from the rules, later warbands have rules that define which hired swords they may hire, but the warbands made just after the rulebook doesn't.
Thus most hired swords should be considered with common sense in mind, dwarves may hire a troll slayer but not an elf ranger, even though they are both available to the same warbands in the core rulebook.
Strike to stun did make a list of this, although I can't find it.