I have seen a JP Sauer M.54 in 5,6x57 (an over/under combination gun) that was both rimmed and rimless. From memory there were 2 extractors. As it was explained to me, getting 5,6x57R rimmed ammo was sometimes problematic, and hence the choice of extractors. Both cartridges operate at the same pressure. I presume this was factory supplied.

I'm not so sure I haven't seen a universal extractor that would handle both types of ammo on another break-open rifle, but I can't recall the specifics. However some have small spring loaded round plungers that slip into the extractor groove. Others have a spring-loaded flat tapered clip that does the same thing. The taper is opposite on each side of the extractor, (each barrel). The latter has a larger area of contact with the rim so is a stronger extraction option, I'm told. Possibly that is the same one that is flexible enough to handle both cartridge types.

I would think that German gunmakers do this sort of work with some regularity to give their customers flexibility. Perhaps, some of their suppliers like Rechnagel would probably sell the necessary parts if that is the case.

I would think that if you search the German terms for this online and search under "images", you might see examples. Look for Patronenauszieher, or Huelsenauszieher, (there's an umlaut (i.e. 2-dots) after the first 'u' so if you get asked, "Did you mean...." Click on that). The extractor pin is called Auszierstift, plunger is Auszieherbolzen. I'd try those words in combination with Drilling, BBF and Sauer 54 and see if the photos or drawings you want appear. A rim, BTW, is Rand, rimless is Randlos.