For the old version of the Placeable Design Kit, where you had to make the modDesc entries, there were two options there. One is DESIGN and the other is COLOR. The design one is for object changes and the color one is for selecting colors.
The new version of the Design Kit does not need the modDesc entries. You just follow the same pattern Giants uses.
For color, it's <thColor1Configurations> - <thColor8Configurations> in your placeable xml file.
For design it's <thDesign1Configurations> - <thDesign8Configurations> in your placeable xml file.