Anyone know anything about Moritz Max Monnig flutes?

I have a friend who is selling a wooden boehm flute labelled ‘Moritz Max Monnig’ on all 3 sections. There is no serial number. It has an old repaired split on the head joint, otherwise it’s in good condition. although the foot joint is slightly loose, but I think this could easily be rectified by re-corking. It plays beautifully in its whole range. The ombouchure hole is rather square and the wood around it is carved, where your bottom lip goes.

Can anyone suggest anything about the history and value of this flute?

Ceri