During the interwar years Sempert & Krieghoff propagated their short drillings with barrel lengths of 55 or 60 cm, about 22 or 24”. The shorter than usual barrels vastly improved balance and handling. They called their short drillings “Modell Waldschütz” = forest shooter. As your’s is fitted with a horn trigger guard, a cartridge holder in buttstock, high grade wood and engraving, it is a “Waldschütz Luxus”.
Afaik, on their early drillings with the separate cocking of the rifle barrel lock by the top slide, the front trigger did not automatically switch back to the right shot barrel on pulling the slide back. You had to push that little button to reactivate the shot barrel lock. Check it out this way: Load the drilling with snap caps or empty cases. Push the selector slide forward to Kugel = rifle position. Now the automatic rear sight ought to be raised, indicating the front trigger will fire the rifle barrel. Pull back the top slide to the Schrot = shot position. Pull the front trigger, but nothing ought to happen, unless you pushed the small button in between.
By 1930 Krieghoff had redesigned their lockwork, omitting the button and the extra movement.