According to equipment_missions.ufo aliens in the early stage should get a plasma pistol (fully loaded) 100%, an additional ammo 100% and also a Kerrblade 100% in this case :

> equipment alien_workers1
> {
> mininterest 0
> maxinterest 79
>
> // Secondary
> item (plaspistol 100)
> item (plaspistol_ammo 1)
>
> // Misc
> item (kerrblade 100)
> }

Imo this should work, because there is enough space for all those items within the inventory and its weight does not exceed the max.

But it does not work. Aliens never get a Kerrblade in this case for some reason, making the equipment system really erratic.