The Korg M1 is highly faked in software (VSTs), but hardware fakes are rare. However, a mismatched serial number indicates a "frankensynth" (a unit made of spare parts).
The first 100,000 units were produced by November 1990 . Korg M1 Serial Number
The Korg M1 contains an internal CR2032 lithium battery that preserves user patches and settings. The Korg M1 is highly faked in software
Korg did not explicitly print the date on the sticker, but the industry has reverse-engineered the system based on thousands of user-submitted units. but hardware fakes are rare. However
If you can provide the , I can help you identify the specific production year of your Korg M1.
Do not confuse M1R serials with the keyboard M1. They are not cross-compatible for dating purposes.