I recently have been looking at a 69 RS z/28 that is for sale. I have looked the car over top to bottom and it appears to be genuine. It was manufactured at the Van Nuys Plant in the fifth week of October, 1968. The problem I have is that the "X33" code does not appear on the cowl tag. Where the X-code normally appears is a code "A661". Is this a real RS Z/28? Please help!!