What it means?

Hi,


I own a luger, with the date 1937 on top of the frame, it is silver-plated, i think it is a navy one.

On the left side of the frame, it has three very samll markins: two are small eagles with the number 63 below each, and the other is a single eagle.

I don't know what this means.

Hope you can help me.


Thanks


Frank