Hi Ahriman, how is your Krug getting along?
Anyway, I recently bought "Armes et Armures Russes" (Editions d'Art Aurore, Leningrad, 1982) which has a number of pictures of Russian armour and weapons.
This was one of the photos. I'm hoping it will bring some sort of closure to the greave/vambrace debate:
I think that the item in this photo does look more like a greave than a vambrace.