I regret the purchase of this box. It came dented, it's already rusting, and I don't like the fact that the locking mechanism is the only way to keep the lid down.
I don't recommend this box
No, the lid does not securely stay closed when it is not locked. It may sit shut temporarily, but it is not designed to remain closed without engaging the latch/lock.
Yes you can replace lock with different key code to match your other cabinets to all keyed the same or even to a better quality lock thats what we did replaced it to a heavy duty barrell lock