Estey & Green melodeons were made from 1855 to 1863. Each instrument was assigned a 4-digit serial number.
Lift the Lid
To find the serial number on an Estey & Green melodeon, start by lifting the hinged lid.
Look on the Back Rail
The serial number may be stamped into the top of the back rail, as in Figure 2. Figure 3 shows a close-up of serial number 5119.
Look on the Exhauster
Serial numbers may be printed on a small paper sticker in the bass (left) back corner of the exhauster. Figure 4 shows serial number 7163 on a paper sticker.
Look Throughout the Instrument
The serial number may also be stenciled on parts inside the melodeon.
Source: Ned Phoenix