Do you mean the original material name, as specified by the imported fbx, as opposed to the mutable user defined label?
If so, I agree it would be nice to have access to something a little less mutable, like a UID or Original Material Name. Most of the time, the Texture Set name is renamed by the user, and usually for good reason. I'd like to be able to track the UID or original material name so that we don't have to rely on the user defined label name so heavily.