I partially agree. Most women in barbarian cultures would be non-combatant commoners (barring the occasional shield maiden, witch, thief, etc). As would children.
As far as men, I would say they were all prettymuch barbarians. Barbaric cultures (especially ones like Cimmerians and Nordheimir) usually don't have standing armies, and all male members of the tribe are trained to fight, and defend their family. So, I'd say, prettymuch all male members of the society would be barbarians (though, maybe only 1 level of barbarian).
Thralls are the hardest to pin down, since that would depend on the nature of Thralldom. If thralldom is hereditary, then they would be a class of commoner. but many barbaric cultures take thralls from cultures they raid, and release them as free citizens once they've completely acclimated to the tribes culture (gone native). So, in that instance, a thrall would likely be whatever class was predominant among the culture raided, until such time as he learned the tribes language and picked up a level in barbarian (and thus was no longer a thrall).
It's a complicated issue, but I'd fall on the side of 99% of male tribesmen have some levels in barbarian, roughly 95% of females would be commoners. The thralls being wild cards that might be anything from commoners to pirates, to enemy soldiers who were too unlucky to die.