Heart says that military stuff tends on the whole to be well packed - remember that these were supposedly shipped brand new to Burma, not flown and probably well protected from the effects of salt water ingress and coated with preservative waxes etc. It was common to bury surplus stuff after the war from what I've heard; Hethel (Lotus Factory) was rumoured to have a hoard of B24 engines and jeeps buried somewhere on site, and MIRA had trouble with magnetic anomolies due to big lumps of ferrous material buried by the RAF.
Good luck to the effort I say, and I hope they find something useful (although my head does say that nearly 70 years in under rain forest might only yield oxide and rotten wood). Give me a shovel and show me where to dig!