I don't know how unique it is. The flag itself may have been mass-produced and sent in bulk to various veterans' associations, where they were then customized with the individual city or town names. But its in good condition, it's got a village name on it which ties it to a place and, to some extent, a time. So overall its a nice artifact from the WW2 era.
Maybe not a great candidate for repatriation, though, because it isn't tied to a specific person. And for Kanegusuku village it might be a not-so-welcome reminder of Japan's militaristic past. The militarists and the government in general didn't treat the Okinawans very well, and the post-war era was also rough for Okinawa, so this kind of item is a bit awkward, I would think. That's my opinion though - and I'm not a native so I could be wrong about it.
Enlarged a bit to help.
en.wikipedia.org
