Dear Christian, I think it is possible. Furthermore, I figure it was likely for a member of the k.u.k. Erzhaus to be an honorary member of it. The extended badge looks like the Matrikelzeichen too. I was trying to find a photo of this decoration on the Net, but I wasn't able to find any. I will make a scan and will post it on the forum. I think that a member of the imperial house that the Archduke was must have had a variety of foreign orders. Notice, however, that he is not wearing any other ones on his tunic. He may have chosen to wear only his Austrian decorations. Well, as I said the photo is not clear, so I am not insisting. Best regards, Lukasz