Have an old M.Hohner I just acquired, what few, [very few] I’ve found online do not have any info. as to date, etc. sending photos in hopes you can date this and add any info. I might be educated with. I have more photos, but think this may do you.
The Regulation Band was produced between 1905 and 1952. There were different versions of it (one with a chain, one as a back-to-back version, different cases).
I’m afraid I can’t tell you the exact production period of this model with certainty.
It is interesting how many harmonicas were inspired by Brass bands of the day. A time when brass bands were very popular and part of many communities. From there the harmonica, or mouth organ bands, evolved also.