Found these four coil stamps in some kilo ware. There are two types, the first were coil stamps printed in December 1920 . The Type II, started to get printed earlier in August 1920. By Type I the middle is usually decentered, the bottom words "DEUTSCHES REICH" are always decentered and a little bigger than type II. Type two has everything centered. This is because Type I was printed with two plates and Type II was printed with one.
The Michel CV is €40 for a single stamp. The Cancel: (KONSTANZ * 1 b)is listed as possible false. I will have to get these proofed. There is a bit of ink from the cancel that goes through to the back, not to much to make it ugly. So I am of good hopes.