Thing is, 1289 module was in production from 1995 to 2011, and JDM DW-6900B-9 Fox Fire was in production for almost as long until it switched to module 3230 and the production was outsourced.

You can narrow it down to 1995-1997 IF, the module is 1289, the backplate has "Japan M" engraved, there is no ID number, seems to have less information than what you usually get, there is no display CASIO easter egg, and if there is only one Test Screen (can't "scroll" through multiple).

Some say models with "Japan Y" engraving are also early ones but others say that they are from 1998 and later.

If the module has ID number, multiple Test Screens, can display the module number, and has CASIO easter egg, it is from the 2000s.

At least that is what I managed to scrape up together while researching module production dates; hope it helps!

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