I am the original owner of this extremely rare Casio made in Japan. Y stands for Yamagata Japan. Gold Button G Shock 240 DW-5200 C-9...the C-9 was not printed on the back, but it stands for the gold model.  They made one other but not gold. My father purchased this new for me in 1984.  The screws and buttons are gold.  The watch works flawlessly, except the light just stopped working, which could be the battery.  Please look at the photos in detail. I'm in no rush to sell it.

Thanks