Really neat that they mate & my hope now is that is across the board on other Merkels. I would say the ejectors were on German platforms for the elite Pre-WWII and are not common but not rare. Now on Pre-WWII Austrian - Ferlach platforms, rare just might be the case. On Post WWII German offerings, they became more common place. The Post WWII time period for your Kombo is very interesting because the Big European Retailers and looking in every corner for guns. Since Russia occupied Suhl, the bulk of their guns went to Russia where Hunting Weapons had not been available to Hunters since the late 1930s. So Retailers looked to Ferlach for as many as they could get in amongst the British Orders during the British Occupation. One sees many guns dated before they were supposed to be available to the Hunters.
Hochachtungsvoll,
Raimey
rse