I picked up this Rheinmetall 12 gauge. The gun has 28 1/2" barrels and still has the 2 9/16" chambers. I assume 535 means made May of 1935? I know Rheinmetall did and still does manufacture military weapons/defence systems. I can find very little on civilian arms and what I did find deals with semi-auto shotguns. Can anyone give me any history on their double barrels. What years did they produce them? Were they sourced from someone else and just their name put on them?