other than the white cloth, these designs look nothing like how they were described in the books. In the book there was white cloth (why they got the nickname whitecloaks), but the cloth was worn over actual armor, and they wore helmets. I didn't notice it before, maybe you are right in that those belts indicate rank designations. According to the book description of rank:
The left breast of each has a golden sunburst worked into it, a symbol of the light. Each garb is further adorned with silver lightning bolts for under-officers and golden stars or knots in increasing quantity to indicate rank for higher officers.