There's always the possibility in the OBL raid, that after the hit itself, a sizable piece of a redundant experimental helicopter was dropped on the site (maybe from one of the CH-47s reportedly involved in the raid) to:
- Make an iconic photo opportunity of an otherwise pretty nondescript location.
- Give other nations the impression that the Americans were further ahead with putting stealth helicopters into service than they really were.
- Add a significant amount of 'wow-factor' to the story.
- Establish the level of co-operation between the Pakistanis/Chinese and/or others, before the subsequent retrieval of the 'wreckage'.
The Americans would have been well aware that the wreckage would soon be inspected by knowledgable foreign parties, thus a film set type mock-up would have been rapidly outed. Whatever was left behind would have had to be pretty convincing.