That SPD should make it a '67 car, as previously stated, but the Poly says '66. Sounds like a customized car to me.
It's not unheard of for cars built at the very start or end of production to use some parts from the previous or later model year, but the description sounds more like a car that was altered, not produced. I'd be that if you get a look at the backsides of the body side panels you'll find that the molding holes were welded/filled.