Jake, to ease your pain I checked a 20 NID that I have that has 28" tubes but otherwise is a close twin to the one you are looking at. Its serial# is 443262, both barrels are .614 bore and are marked 4 on each barrel flat; the chokes on each tube start at 2 1/4" from the end. both barrels have about .004 at 2"
. You really need to remove the barrels and check the choke marking on the barrel flats, 1= 1/4 choke, 2= 1/2 choke, 3= 3/4 choke 4= full choke. If you get the serial Walt can tell you how it left the Ithaca plant.
Jim A.
