Gene: the Perron just indicates Banc d’Epreuves de Liege
There were 3 provings and the Perron could be applied each time, but typically just at the 3rd proof:

First Obligatory (Provisional) Proof Load for “Double-Barreled Breech-Loading Sporting Guns” - breech plugged tubes
Marked with Script EL AND a controller’s identification mark.

Second Obligatory Proof - joined barrels, fine bored and finished.
Controller's mark

Third Obligatory (Definitive) Proof - finished barrels attached to finished action.
ELG mark in an oval; crowned after 1893 (for breechloading guns) AND a controller’s identification mark.

https://sites.google.com/a/damascusknowledge.com/www/home