Yamagata Ken,
for training drops the jerry cans would ether be empty or contain water. For Exercise or Operations they would contain fuel for the vehicle. For a war load you would hardly see the vehicle for jerry cans and other stores !
Pic of the HSP fully rigged and the final checks being completed and signed for. Both the ALM and the army checker did their own independent checks and then signed the checklist.
You can clearly see the extractor parachute fitted to the bomb rack.