H5e,
These bikes sometimes have a VIN, sometimes an old-atyle frame number.
the VIN can be decoded by the usual means.
KX125J = 92/93
KX125K = 94 ~ 98 (although I haven't seen a 96+ with the old style number - only with a VIN).
The most likely give away is the colour of the upper fork legs.
If its a 94+ one, I want the clutch cover (or what's left of the motor).