The year should be coded in the VIN number. Here is a site explaining VIN coding on ATVs.
http://www.atvstyle.com/atv-vin-number
As far as chasing down a fault, Start at the starter circuit .. Since you get a spark when you release the start button , it indicates to me there is no current to the ignition while the starter is activated , but there is when it is released. I would strongly suspect the starter relay or the wire from it that supplies ignition current when it is activated.