I don't know the details of COM so I wouldn't recognise the GUID for IUknown.
I was suprised to see COM's IUknown interface makes an appearance in the WS-Transfer specification. If you look at the second example the WS-Addressing MessageID is 00000000-0000-0000-C000-000000000046 the GUID for IUknown.
This was from Benjamin Mitchell's blog.
There is no chance this was done by accident. Who said that MS doesn't have a sense of humour? 🙂