There are no stupid questions, and I am a very patient man. It was originally a cape gun. SXS configuration, but one barrel was a shotgun (smooth bore) and one barrel was a rifle barrel. Very common in Germany as there are no "seasons" all game is open at one time. So you were prepared for the bird as well as the buck. One gun, two different purposes. They also had guns called "drillings" that were a SXS shotgun with a single rifle barrel under but between the two barrels. Both guns are still made, but very pricey as you can imagine. This gun was re-barreled in 1935 as as a SXS shotgun only. The new barrels could use the new nitro powder which made the old cape barrels obsolete.
Combination gun - Wikipedia, the free encyclopedia