Regarding Locked Items

Just wondering, since I know you're a programmer. Can you extract the data on whether or not it expires?

That's something that would only be visible in the server side representation of the object. The wz files are only a template, a base model of default values. Anything that modifies those values occurs server side and can only be seen by Nexon.

The previous analogy of hair is suitable though - Your hair coupon may expire, but once you've used it to change your hair from being hair type 11111 to hairtype 111112 that's a permanent change of a property.

There are no time limited changes of that nature. Everything is either a specific value, or it isn't. The only way the locks could expire is if they really still exist somewhere as a physical item and are only bestowing their effects by presence of that item (like the way a friendship ring bestows it's effects until they expire). But because the actual lock item disappears from your inventory when used it doesn't appear to be an "effect" but rather a modifier like a hair coupon.

Also note there are no other "temporary" item effects, making this even less likely to be truly time limited because that requires an additional level of sophistication built into the game.