Interesting! I knew that he bones were lost in the early days of WWII but had not heard that they were supposed to be headed to the Marine barracks in Peking.
Coincidentally, I recently read this novel 
set about American marines in China, December 1941.
If the taking of the barracks occurred as related in the story, it is doubtful the bones ever left China.
Whatever happened, I doubt that they will ever be found.
The chinese had a habit of grinding bones for use as ‘medicine’.
I suggest that it is more likely that one of several million chinese did that, than one of a few hundreds of marines took it, AND survived WWII.