If you're talking about
this, the answer is yes.
I have a UFS v2 and an extra upper body (v2) and tried to put Iatty in it, but it wouldn't fit, because this v2 upper body is thicker than v1. So I asked imeo if I could use a v1 upper in my UFS and he said yes, because the
threads are the same. So I'm waiting for a v1 upper body to try it.
So v1 and v2 upper bodies are interchangeable.