sir-boformer

var defaultShader = Shader.Find("Custom/Buildings/Building/Default");
var fenceShader = Shader.Find("Custom/Buildings/Building/Fence");

var asset = ToolsModifierControl.toolController.m_editPrefabInfo as BuildingInfo;
if(asset == null) { Debug.Log("Error: Not a building!"); return; }

if(asset.m_material.shader == defaultShader)
{
  asset.m_requireHeightMap = true;
  asset.m_material.shader = fenceShader;