Even if it looks like swept wings, the image is basically like a shadow. You don't know how the object is oriented. Yes, it looks like an FJ-4, but it could also be a WWII era carrier aircraft with wings partially folded. Some of them stowed in a "swept" configuration.
The ferry route to Australia took aircraft to Christmas Island, then Canton, etc. It could easily be a C-47. When you have a blurry mish-mash of an image, the nose section, engines and slightly swept wings of the C-47 might look even more swept.