If there is NO stamping of COO, then one is to presume that it's made in NA.
Dornbracht is made in Iserlohn Germany. Even the sub suppliers are based within 10 kilometers of the factory. I cannot say if Kohler is sourcing from China, but i can tell you that Dornbracht is not. As a premium brand, going the cheap route is bad for our reputation.
*In full disclosure, I am the current Technical Services Manager for Dornbracht Americas Inc.