I was told on numerous events that never say "never", or "unquestionably".
And BTW, it's listed as vambrace in a TURKISH museum... in Ankara.
I have made something like the pic I posted, and it was comfortable for fighting with sabers, and it restricted only a bit movement, less than an italian mitten. Of course, it wouldn't be fixed to the hand, but to the lower arm only.
BUT it'd work as a greave as well. I personally don't like the idea much as I don't really like fighting from horseback, but it'd work for those who like it. Strange thing is that most of these "greaves" DO look like my forearm in proportions - much more than the "true" vambraces. Only a few are too long, and the RA photo of the assembled version is the only one which looks definitely like a greave to me.
I'm almost sure that we'll never find out. Or do we have any illustrations/sculptures/explicit writings? And from where the turkish museum thought it's a vambrace? Good questions, I think.