It is possible to retreive the GUID. There are some Dynamo scripts out there, one from David Ronson of TD (presented at AU a few years ago), and the other Darren Young. Also, if you are familiar with building macros in Revit (C#), we got this code line from Martin Schmid of Autodesk, and added a few things to the macro. (It will display GUID and Version number - you need to verify/ modify both in CADmep/ ESTmep), then place those in your windows clipboard:
public void GetGuid()
{
Autodesk.Revit.DB.FabricationConfiguration fc = Autodesk.Revit.DB.FabricationConfiguration.GetFabricationConfiguration(this.ActiveUIDocument.Document);
Autodesk.Revit.DB.FabricationConfigurationInfo fci = fc.GetFabricationConfigurationInfo();
string FabGUID = fci.GUID.ToString();
string FabVersion = fci.Version.ToString();
TaskDialog.Show("Fabrication Configuration Details", "GUID\n" + FabGUID + "\nVersion\n" + FabVersion + "\n\nAfter closing this window, this data will be in your windows clipboard. To retrieve, paste to Notepad.");
string guidAndVersion = string.Format("GUID {0}\nVersion {1}", fci.GUID.ToString(), fci.Version.ToString());
System.Windows.Forms.Clipboard.SetText(guidAndVersion);
}