That Austrian double eagle appears to be a complicated matter.
I looked here
http://austria-forum.org/af/Wissenssammlungen/Symbole/Doppeladler

Conclusion: the eagle here is the form used in Austria between 1806 and 1915.
The Austro-Hungarian form looks different and came only in 1915.

The eagle plaque in the rifle case here looks as if it was cut out somewhere else. And I cannot imagine a reason why it should be there, except deccoration.

fuhrmann