The costuming requirement is that they look uncouth and uncivilized, and that fur and leather are included in the costume. There are certainly barbarians out there with steel breastplates and the like, but it is all about how you accent it and the other costuming you have. The armor you describe would be just fine. Add some fur or leather trim, a belt pouch with some fur or leather and make sure you have an overall 'savage' appearance and you are good to go! As always, consult the local (SoMN in this case) player marshal or plot team to make sure you are within the requirements they want to see for a race.
Enjoy playing a barbarian! <3