Steve your right about hasps, I've got a MkIIA1 grenade packing crate with the exact same fittings, and did own a packing crate for clips of 30-06 in 5 round Springfield chargers. The grenade box is somewhere at a local museum that I'm a member of, and the 30-06 crate has disappeared somewhere back in the mists of time, as I've not laid eyes on it for about 15 years LOL. But they are most definitely of that design.
The small lead seals are off ammo boxes etc, if you look at the hasp they have a small pressed lip which is raised, the catch for the hasp is also key shaped and is hollow in the centre, these boxes could be secured with a small padlock, but also had a seal wired in place thought the whole lot, via the little pressed lip in the face of the hasp. Also on standard army type, pressed Metal .50 cal boxes made by Reaves etc, the wire seal went though a small bracket on the front face of the box, which is in the centre of the box and locates with the flap when the lid is shut.