My Japan made ones have a serial number except the DW-6900FS.
My Thailand made ones don't have a serial number except the GBA-800.
What mandates a G-Shock to have a serial number?
I have DW-6900FS with Japan caseback/back plate and Japan buckle/clasp but it does not have a build date/serial # in the caseback/back plate and I bought it from a reputable seller. I don't think it's fake but the lack of a build date/serial # in the caseback/back plate is making me doubt its...
I want to but not right now, I just bought 2 G-Shock in the last 2 months! The prices are going higher and higher We'll see if I can save enough to get the next one.
It looks like an orange unit (#6) with a gold outer cover protector (#1).
There should be a white sticker on the underside of the box which would have the actual model number.