I am interested in a 1900 M&H, but the serial number looks like it was written in with a marker, rather than etched into the metal. Is that how M&H serial numbers appear inside the piano? Seller sent me pictures, but I'm afraid I don't know how to attach a picture to this thread.

A piano 111 years old has likely been rebuilt -- probably several times. It's common to repaint the (metal) plate, and to redo the serial number with a marker pen.

Serial numbers for 1900 began with 11,800. You can also lift up the strip of wood covering the front of the keys, and check the backside for a stamped serial number. It's usually found in several places in the piano.

In any case, you'd want to know as much as possible about its maintenance history.

--Cy--

Well, no, the number on the back of the keyslip is not the serial number. It will probably only be a bit higher, however, which will confirm whether the number on the plate is correct. The case number on my living room Mason & Hamlin is about 500 higher than the serial number. It dates from 1923, so I would suspect that the number on the back of the keyslip will be closer in 1900.

Thanks, but now I'm more confused. The serial # is 15507. It has never been reconstructed.

That would be 1906.

Thanks, BDB. Actually, the seller said some work has been done on the instrument.

Get a tech (or a rebuilder, even better) to check it out and assess its condition and any work that was done to it.