The numbers indicate a slightly overbored 20ga. CL is cylinder. Other than that, as Alder said, the typical Italian choke marks are by stars. But back during that time period, a lot of Bernardellis had the somewhat unique choke combinations of IC/IM and C/M. I wonder if they might have used CLM for modified? Can't recall ever having seen that. Or maybe modified cylinder . . . in other words, IC? Only way to know for sure is with a bore and choke gauge.