The extra pictures of this duck just seem to confirm my suspicions about Mtarfa. It's in a colourway that I thought was Mdina for quite some time, and have been trying to collect, because I like it so much, but recent purchases have positively id'd it as Mtarfa. I still think it's wonderful and am still collecting it.
I think it does have slight irridesence, but it's inside the glass, under the final casing, the silvery bluey yellowy bits.
I'm really not into ducks, but I would make an exception for this one - it is gorgeous! Lucky you! :mr green: