Maybe it's the effects on the guitar that make it sound different?
It could be, however it could also be an older Korg like the i30 or pa80... I dont think the essence of the Korg PA sound has changed much over the last decade..
This is what makes it so hard to guess the model, even now, from PA300 to PA3x all instruments have basically the same sound engine.. Which is basically an evolved version from the engine in al previous PA arrangers.. And possibly even the i30