Ok, I'll try to post some pictures, hope it will help. In the following posts I will discuss only 1st class crosses.
1. The obverse picture of Rossbach cross published in July 1943 in Der Reiter gen Osten newspaper, and the cross from my collection which IMO is a perfect match to it.
Having in mind untypical set up which can be only met on some decorations produced in 20-ies, I'd say that we see here the 1st run of these crosses.
2. The obverse picture of Rossbach cross from Klietmann's book dated 1979, and the matching specimen from Hartung catalogue. Having in mind the rarity of this version , and also the set up, I'd suppose that we see the additional edition awarded in 1933.
Honestly said, that's it. I've never seen any other 1st class crosses which have any provenance. Of course we can't exclude private purchase items, but they are a question of believe and proper hand inspection
As for the cross in the beginning of the thread....ufff... personally I do not like it. First of all it carries the design of these suspicious items which Brian describes as produced in 50-ies and we used to consider fakes. Please find below one of them for comparison.
What makes it even worse, having the design of later production, the set up of this cross is trying to imitate the early one (?).
And last but not least--the source. Brian can tell us more about the seller, I will just mention that some of the fake Freikorps decorations from this person are really well made and are not serial/unique. And what a coincidence, just few months before he also sold one of these "50-ies made" items...