On the swiveling lid with the little metal stop, the bottom of the lid is notched to accept the protruding stop, terminating at the point that the lid is in the proper position.
I would think that you would need a bit of tension on the pivot screw, to keep the lid from opening inadvertently.
I was wondering if the "stop" was made of silver, as it shines so nicely.
Interesting to see the variations in the manner of moving the lid to access the cavity, and locking it in place when closed. Nice to see many different ways of achieving the same goal. We are a creative bunch, aren't we?