You can't do that on l2j servers. If your server had OFF files it would, guess what? only C4 servers have 100% OFF files maybe C5 but I'm not sure, others are just fake l2j. Even if I would send you NpcName-e.dat.. all chests
ALL would be good ones.
Cuz' l2j chests are not 100% boxes... server alone chooses if it would be a mob or a box, while you are opening them.
Use search... next time.