have you checked under the barrels ,,pul the forarm off and break the action open,,see if they may be marked underneith,,possible with a choke size like .XXX or M,F,IMP something like that..
bigcurt
I found out, they didn't mark them unless they were made different than full, modified on a 28 and 30 inch. So no marks, full and modified on 30 and 28 inch, 26 inch no marks were modified and improved cylinder.