Hi, Moritz,
this only shows, how much specialist knowledge is lost during the last decades - or let's say it differently, how successfull the marketing experts have
been with their strategies. There's just so much semi-knowledge around......
Traditionally German silver (aka Maillechort, nickelsilver, alpaka, in German "Neusilber" ......) was the prefered metal for movement plates/bridges
of especially flat movements. This included also the very complicated movements, as structural strength was very important there as well....German silver
is harder and stronger, thus allows for a bit more freedom when it comes to the limits.
Now, traditionally those especially flat and delicate movements where the strength of the swiss manufacturers, Geneva companies (most of them with VdJ delivered complicated movements).
The German (and here especially Glashütte) companies traditionally produced exactly the oposite sort of watches, everything was thicker, stronger and
more than bullet proof. You'll find this from base plate to case - everything is onthe large, thick side....watch cases beeing sometimes three to four times the weight of a comparable swiss counterpart.
German silver movements - made by Glashütte companies - were the minority and in fact very, very rare.
The modern Lange marketing, trying to connect the German silver as typical traditional German watchmaking, is more than weird - but funnily enough
it obviously worked.
A bit sad, in my eyes, that even the todays "experts and connaisseurs" buy into this, even without asking .
As to your question, yes, the 5959 movement is German silver and yes there are more.....yes, two times assembling isn't too uncommon , especially with hand finished technical components as in this caliber - every single spring and lever is hand finished to a large degree here. This also includes a great part of the technical finish (strenght of the springs in critical parts, technically important parts of the levers....).
Best regards
Suitbert