I’ve a flute quite close in appearance to the one in question. It is not a ‘Nach Meyer’. It plays well at A=440 with a 5 MM slide extension. It is well in tune with itself. It is, HOWEVER, rather small bore and quiet voiced. NOT a Session cannon. On very close examination with a bright light the wood, which at first sight appears to be black has deep red highlights, leading me to believe it is cocus. The keywork is hard to pin down. The angled G# level looks German, but the high quality GS and extended ‘points’ where the key levers cross the key cups appear French. I have seen Swiss flutes of similar appearance. If you can get it cheaply enough it may be a good practice flute.
Bob