I don't think it's upside down, but looks like on the "wrong" arm, though that's debatable depending on handedness.
The more I think about this though, this seems like only one of several fundamental issues with this thing :P
I also mouse right handed because in the early days there was no such thing as an ergonomic mouse and it often wasn’t easy to change the settings to reverse the buttons. It does mean I can mouse and write at the same time.