Sorry, I can't find any more markings, except 18.5 choke and 1500 grams (probably the weigt of the barrels). And where are the barrel flats on an over/under? The first and the second picture in my previous post are the markings found just above the lumps on either side of the barrels. I have not removed the two wooden bits of the forend that are attached to the barrels, I do not have the right turnscrew.