COM interface with Python: Cant access the Name property of an AcadBlockReference object

I try to find out the which block is refferenced by a AcadBlockReference

    import comtypes.client

    acad = comtypes.client.GetActiveObject("BricscadApp.AcadApplication")

    doc = acad.ActiveDocument

    model = doc.ModelSpace

    model(121).ObjectName

This gives the result: 'AcDbBlockReference' - 121 is indeed a block reference

Now I try to acces the name of the referenced block:

    model(121).Name

I get the errormessage

    Traceback (most recent call last):
      File "C:\KBApps\Python34\lib\site-packages\comtypes-1.1.1-py3.4.egg\comtypes\__init__.py", line 275, in __getattr__
        fixed_name = self.__map_case__[name.lower()]
    KeyError: 'name'

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "", line 1, in
        model(121).Name;
      File "C:\KBApps\Python34\lib\site-packages\comtypes-1.1.1-py3.4.egg\comtypes\__init__.py", line 277, in __getattr__
        raise AttributeError(name)
    AttributeError: Name

I cant find the reason for this. The COM documentation says that an AcadBlockReference object has the property Name. 

Best regards

Heinz-Otto

(Win7 x64 SP1, Bricscad V14.2.11 (x64), Python 3.4.3 64 bit)