Left Barrel KG 1,330 (barrel weight = 2# 15 oz) and 18.6 (bore = 0.732") and 17.1 (muzzle = 0.673") That would give you 0.059" of choke constriction, which seems like way too much. Maybe I've missed something here.

Right barrel Number 70 (chamber length = 2.756") and then 20,3 (0.799" not sure about this one) and then 18.3 (0.720") and 17.4 (0.685")

For the left barrel I'm guessing that the KG 1,330 is what it is proofed for. The 18.6 is the bore size left barrel and choke of that left barrel is 17.1.

For the right barrel, I'm guessing 70 is chamber size. No idea what the 20,3 would be. And then 18.3 is bore size and the 17.4 is choke constriction.