If you look carefully at the caseback, there is a gap between "Bunde" and "swehr". That makes no sense at all in German - it's a single word, but if you were going to separate it, it would be "Bundes" and "Wehr". Even that makes little sense because the "Bundes" would no longer need to be genitive and would revert to simply being "Bund". So whoever made that caseback appears not to have knowledge of German and you have to figure that the original would have been made or at least engraved by someone who did know German.

All in all, I'd steer clear myself, better safe than sorry and all that.