I had both versions on the bench recently and it definitely appears IF they are exemplary of what is available that the "one piece" is very machinable down to the original version.
I'm not sure what the thinking is with the original design vs. the one piece integral with hub, since it would appear that there is less machining with it then the current integral hub/rotor version has?
Considering the current state of the "original" version being more expensive then the one piece is suggests to me that they are starting with the one piece casting and machining them down? That would have to be in a cheap labor market like China or somewhere else "offshore"?