Good Morning
Interesting. I have part of the original catalogue issued by Paul Krog. I think the 70,s, in which he gave outlines of all his Gottstein figures with coloured pictures for the painting details.
On each page he has as the header Gottstein, Blum, Kollbrunner which I believe are the owners or Editors of the moulds and do not relate to the maker of the moulds.
I have always understood that Gottstein was the first Editor, the moulds then passed to Blum who was more of a collector and did not or very rarely issue any castings, they then passed to Kollbrunner, and on his death to Paul Krog.
I would suggest perhaps that you try to contact Adrian Forman who has a web site in which he describes that he was publishing the definite work on Gottstein, never published but I understand that he has original archive material on Gottstein, and that he is currently disposing of some of his collection of flats.
Recently advised on EBay.uk was some Madelener flats at very high prices.
All a bit vague Sorry
Kindest regards
Bob
Perhaps an enquiry might get lucky??