The BH chassis cars in the US had the smoked finisher panel, so swapping just the tail lights matches up pretty well with the "SUBARU" USDM panel.
On the BE chassis, the USDM finisher was not smoked and much more red, so the JDM pieces are significantly different. Here is my car with the JDM finisher and USDM lights:
As for driving an Outback and not a Legacy.. in Japan, it was just a trim level called the Legacy Lancaster. Much like the USDM 1st gen, called the Legacy Outback. The solo Outback name was not used until the 3rd gen Outback/4th gen Legacy platform.. 2003MY in Japan, and 2005MY here.
On the BE chassis, the USDM finisher was not smoked and much more red, so the JDM pieces are significantly different. Here is my car with the JDM finisher and USDM lights:

As for driving an Outback and not a Legacy.. in Japan, it was just a trim level called the Legacy Lancaster. Much like the USDM 1st gen, called the Legacy Outback. The solo Outback name was not used until the 3rd gen Outback/4th gen Legacy platform.. 2003MY in Japan, and 2005MY here.