I had one. It was a perfectly standard 5100. Adjusted properly it ran to within 5 secs a day, no problem.
I understand it was issued with a tight tolerance of adjustment, but no other changes.
It was issued with the star map, as the fabled Sternzeit Reguliert Heuer Bund was, but that is its only connection with Sidereal time.
IMHO it was intended to be a precise military chronograph, not one limited to the navigational use only, by adjustment to sidereal time.
BTW Herr Tengler ordered 600 cases, I have seen a copy of the order, so there should be that number in total.
If it's Lemania-powered, I'm interested. Tool Chrono - interested. Dive Chrono - interested. Interesting - interested