Nice Kammerlader. I saw it before on the Gunboards forum...The brass buttons is for attaching a small piece of leather. It can stay in two positions. Across the hammer as a safety, or out of the way.
I made a thread about the development of the norwegian Kammerladers on Gunboards, but there wasn't much interest. I find these old pieces quite fascinating.
The birth of the Kammerlader.