There is no mention of this name is The Italian Gun by Smith and Morrow. It seems strange to find word 'Acier' on barrels of Italian gun. Never heard of barrel steel from Roelher either.
There is Bohler Bros. light steel, Rohr, Roeschlings, but I don't seem to recall name you have mentioned.
Your only hope lies with 'Italo' that can understand works written by Marco Nobili.