For the encircled LB, somewhat oval in nature, probability lies toward Lhermite & Bruyninckx:

http://www.littlegun.be/arme%20belge/art...ninckx%20gb.htm

I believe the concern was centered around fishing components so there's some question of their involvement as well as a lack of info. The stamp is on both tubes but worked off some on the right. As Peter mentions, times were becoming difficult & concerns would switch horses to make money on what they could. So it is possible that fishing component supplier Lhermite & Bruyninckx somehow made or finished the tubes.

http://www.doublegunshop.com/forums/ubbt...true#Post155612

cross ref to previous encircled LB thread:
http://www.doublegunshop.com/forums/ubbt...true#Post155612
where an Louis Brancquaert of Brussels is mentioned but the general consensus is that he was a firearms merchant:
http://www.littlegun.be/arme%20belge/artisans%20identifies%20b/a%20brancquaert%20gb.htm

Can you tell how many words, or sets of letters, on the phrase that's been scratched thru? Between the 455 on the lower rib & the scratch what is stamped between them on the underside of the right tube?

Kind Regards,

Raimey
rse