It actually refers to the blade shape. Like the Filarmonica 14 is a blade shape style not limited to Filarmonica, other German manufacturers also had #136 razors. That isn't to say they also used the opportunity to attach it to a Union regiment.
As for the tortoiseshell, it was a hope, not a guarantee. What do you think it is? Dyed horn? Plastic?
Edit: this is the post I sourced that info from:
www.badgerandblade.com
Though to be fair, nowhere in that post does he say that the Henkels is older than the Torrey. He clearly goes on the assumption that the "our" references their particular version of the 136, which may or may not be true.