Yep. Cockerill made the Siemens-Martin steel used by Laurent Lochet-Habran to make the tubes. There may be the barrel maker's initials somewhere also.
Same stuff used by almost all of the U.S. double gun makers. The ‘LLH’ mark is frequently found on Fulton and L.C. Smith Royal, Armor, London, Crown and even Nitro Steel barrels from 1914 to 1948, and also Fox, Ithaca, Lefever, Crescent, and Baker guns.
Buturlin cited studies conducted at TOZ (Tula Arms Plant) likely immediately before WWI listing Russian Siemens-Martin tensile strength as 85,300 – 92,400 psi so it is clear that the composition was modified compared to the original process steel, and multiple products were no doubt offered based on the intended application.
Pre-WWI Siemens may have been similar to AISI 1021 - 1034 Carbon Steels.
"The Sampling and Chemical Analysis of Iron and Steel", 1915
http://books.google.com/books?id=03w6AAAAMAAJ&dqThe 1918 Sears catalog states the Hunter Arms Fulton Gladiator “barrels are made of a high grade carbon steel, having a tensile strength of 85 to 95 thousand pounds to the square inch.”
