I have a sweet sounding vintage Alto from Couesnon. It's an Monopole Conservatoires model made at 105 Rue Lafayette Paris. It is silver plate with rolled tone holes and a double neck hole. It is stamped made in france and it has a serial number 76xx. It has origanol case with bake light handles.It plays like butter! I believe it is 1931 to 1949. Can anyone narrow down the date for me? It's a great stress reliever and I would like to know more about it!