Serial number? No, unfortunately the concertina had been altered and had no serial number when i got it. It's a 48-key Lachenal with black and white buttons. The reeds seem to be a mix of brass and steel to my eyes, (is that possible?) but I am no expert. So how do I know it's a Lachenal you may ask. I think thsis was the conclusion of Stuart Frank, (now a curator at the New Bedford Whaling Museum) when he looked at it over 25 years ago. I don't believe there is a Lachenal name or number inside. I'll try to post photos soon. - Paul