The ELG indicates a Liege proof.
The weight marked is 1K487.8. They stopped using the decimal notation after 1923. It comes out to 3.28 lbs.
There is a nitro proof which indicates they used did a 4th proof using EC powder.
The 12 C in the diamond indicates a 12 gauge. In use from 1898 to 1924.
The crown over the R indicates a rifled bore.
Non Pour Raye indicates a smoothbore.
Confusing huh? I have seen this conflict before. It was on a gun that was meant to fire both shot and ball. This would make sense with a gun destined for the German market, where multiple use guns are highly prized.
Unless someone can offer another explaination for the crown over the W, I believe it to be the makers trade mark. While not documented, from the quality of this gun, I would guess that maker may have been Wilmart. For a much later example of Wilmart:
http://www.littlegun.be/arme%20belge/artisans%20identifies%20t%20w/a%20wilmart%20gb.htm Unlike some other countries, apparently the Belgians did not register their trade marks with the proof house. In the case of some better known makers you can find examples of the mark changing over time.
The X with * is the controller's mark.
If there is an eagle present, I do not see it.
Oh, by the way. Those barrels are great! What a beautiful pattern.
Hope this helps a bit.
Pete