Korjean

This guitar was my grandfathers and he recently passed and no one else is the family is musically inclined. We had it evaluated at a local music store and I posted it online based on what they told us. I just had someone tell me it’s fake and we are falsely advertising. So, what are your thoughts based upon the pictures? There is no identifiable serial number and that is the basis for the person saying it’s a fake. Please help!