Ravanar wrote: the only real difference is that storm troopers are trained at the schola progenium where as Kasrkin are exclusively from Cadia.
Yup.
It's really the fact that they have hellguns that gives them away as stormtroopers. Of course, if my opponent showed up with kasrkin models to represent vets with the grenadiers doctrine, I think that would be a cool way of doing it.