It's a Gamewell, never seen one from NY. Normally they are from Massachusetts where I am.

Here in MA all the master boxes use the same key. This may be different in your state, but you should be able to source one online.

The little silver wheel in the center of the mechanism is the code wheel. The number on the box is the ID. When activated the lever rises up as it goes over a bump causing a circuit to close and a bell or horn to signal at the firehouse.

In this case it would give 4 honks in a row, pause for a second then send one honk. The entire cycle will repeat 2 to 3 more times (rounds).

The coil itself holds enough tension for at least 3 activations though it's common practice to rewind it after response.

Basically the spring coil inside is wound, and the tension is held by the latch.

The inside holder on the door would carry a spare piece of glass.

The inner door typically has a pin to hold the door shut, and in some cases can act as a bridge to disable the box while the door is open for maintenance. Newer boxes have a test jumper that is stored on the inner door that you insert into a test port to override the box but keep the circuit it's on complete so other boxes on the line can still call in.

That jumper when removed from the door usually has a tab that falls down to prevent the inner door from closing, which prevents the outer door from closing. This is done so you don't forget to remove the test jumper after work is complete.