[jhv48]

If you registered it as a 60's cobra (when in fact it wasn't) and tried to sell it to a buyer in California, he could be faced with fraud charges and the impounding of his vehicle if he transferred the registration to his name as a 60's car and got caught. You see, California's registration fees are based on the year of the vehicle as well as it's value. He would therefore be cheating the state out of its share of reg fees. Thus the fraud. He would need to change the year of the car to the actual year of completion, pass that year's smog regs or apply for an sb100 smog exemption.
So, yes, it can affect the value of the car to buyers in some states if it is registered improperly.