You're right Malsa,but they say here
http://www.moddb.com/mods/mare-nostrum that has been added "LG 40 specific optics" (could be the name of that optics?).
And according to the wikipedia M13/40 page (yeah, i know not the best source) in italian "Tutti gli strumenti ottici furono costruiti dalla ditta San Giorgio" (All the optical instruments were built by the company San Giorgio). Unfortunately I have not found any picture of that optics.