It is Jean Falla gun as Daryl stated.
http://www.littlegun.be/arme%20belge/artisans%20identifies%20e%20f/a%20falla%20gb.htm

It was nitro proofed in 1954 according to the lamda date code. Do a search here for Falla and you will see more info.
http://damascus-barrels.com/Belgian_All_Proofmarks.html

If this is your idea of a clunker. I will buy it from you at clunker prices....

Pete