If you have Google Earth, you can see it still laying in the swamp prior to recovery. A pretty fair image, too.
Its coordinates are as follows:
9d 11'53" S
148d 39'42" E
Technically, US naval equipment still belongs to the US provided certain criteria is met according to the following website:
Navy Shipwrecks and Aircraft Losses
Unfortunately, this was a US Army aircraft and probably falls under the criteria as layed out according to the following website:
Is unexploded World War II ammunition abandoned property
My opinion is simple; what is legally right is not always what is
morally right. These aircraft- Japanese ones in particular- are
extremely rare. Recovery for the purpose of restoration (even if only for static display purposes) is extremely important and essential if for no other reason than to preserve the history of a by-gone era.