This circa 1880’s Boehm and Mendler flute plays with the fluidity of a modern flute since it was originally constructed with the “still used today” Briccialdi Style Bb along with a “still used today” Closed G # Key which makes this particular flute extremely playable and perhaps "extremely rare. "most likely a custom order or possibly experimental " This is a usable bit of History that you can admire, play and enjoy. Plays easily at 440 Hz for me with the head pulled out just 3mm. The Wood On the B&H appears to be Pernambuco, but might possibly be another type of exotic hardwood, Cocus has been suggested.
These flutes don’t come up for sale in public in a regular manner, so there’s no way to really make a comment on the price. Boehm system flutes from the top builders are of course much more expensive than 8-key flutes of equivalent quality, whatever that really means.