I've finally (in 2020) got around to putting an article on this site about Einhorn and III./KG 200. I contributed a fairly lengthy version of the story as Chapter 25 of J. Richard Smith & Eddie J. Creek's Focke-Wulf Fw 190 Volume Three, 1944–1945 (Classic Publications, Hersham, 2013) ISBN 9781906537319. That was a shortened version of what I had and I've added a quite lot since.
If this Fw 190 on page 69 is from Sonderverband Einhorn as the publisher's caption says, it deepens the mystery of the Staffel’s code system. I've got persuasive evidence (in the shape of contemporary German records and signals deciphered by the Allies) that the aircraft on page 71 is an Einhorn machine though.