Man, I finally get to respond to one of your posts!/forums/images/icons/laugh.gif I don't know the answer. After seeing the other nice rides you have, you have a very good case for originality. Your Mach 1 will be a flawless restoration of the finest class. Soo,,,,,considering that.....
I would go original if the cost vs repro is not cost prohibitive. I would also investigate where to find quality repros. NPD I'm sure, has good reproduction louvers. I guess a person just needs to weigh out budget and quality considerations. Since I'm budget minded, a nice set from NPD would fit the bill perfectly. I know, I'm confusing,.... confused. hehe.