How to find out a models value

[Zonda]

I have a 1/18 Auto Art BMW 635 CSi touring car. I recently noticed there are spelling mistakes on two of the main decals. I've been trying to find out how many were made like this and if it affects the value but all I can find is that the decals that read Original or Orignal on mine have since been changed to read Genuine.

Can anyone help?