With the earlier Nagel-branded lenses, I don't think anyone has an authoritative history of what came from where.
That seems like too strong a statement to me. You're not saying "no Xenars were ever rebranded", are you?The only really decent 9x12 lenses are sold under the lens manufacturers own name (...)
At some point I'll try to take a really close look at the "Nagel" lens on my 9x12 Fornidar. My feeling is that it handles bright lights too well to be a triplet, but maybe it's just a really good one.