Very nice Rbl. f. 16. Looks very much like WWI manufacture. I have two of these in my collection. Mine are manufactured during WWII.
In the picture below, the one in the middle, and the one the right, are Rbl. f. 16. The one one the left, is a Rbl. f. 32. When you compare your optics, with the two on the right, you can see differences in manufacture. None of mine, has any engraved inscription. I am no expert, but in my opinion, you have a nice WWI example. You have a very kind wife, that would buy something like this for you. Mine probably wouldn't.
All the best
Snoopy