I haven't got terai yuki.  is it possible to compare the mesh of each head, side by side?

Not sure it would give you a lot of insight, since (I'm pretty sure) the figure has been run through the retopology function of a program such as 3DCoat, Silo, or ZBrush. This means there won't be a "one to one" match of polygons. Still, there are some clues in the mesh itself if you know where to look for them...loops that match, contours that match, etc. I'm on the road for the next week and don't have access to Poser on my laptop. If you can wait till the middle of next week, I can show you what you want.

BTW: I emailed Smith Micro about this and they said they really don't care about it as the Terai Yuki figure doesn't belong to them, it belongs to E-Frontier. On the other hand, E-Frontier no longer seems to want to have anything to do with the Western World...so I suppose someone from Japan will have to bring this up to them...

I'd rather stay in my lane than lay in my stain!