Yes, Armor is the only one that has an Enhancement Bonus. Shields and Bracers do not.
From the top of my head:
Base of 10
Half Level
Ability Mod (If Light Armor, use higher of Dex/Int Mod. None otherwise.)
Armor (Hide, Leather, Plate, etc)
Armor Enhancement (+1, +2, etc)
Shield (Light (+1)...