I have a set I bought last year for $300.00..when I got them they were a one piece molded cheap plastic that when you drove down the road fluttered in the wind...I didn't even have the heart to sell them on ebay to another sucker..( me being the first and I bought them new) Do your self a favor...forget louvers...
you can buy mine real cheap. i don't think they are all plastic. they came w/my vette (81) but have never been on it. the guy said he got them from someone else and never used them. they are used, and there really isn't any hardware with them (although i don't think u need any). i was actually gonna put em on ebay but haven't gotten around to it.
My '84 Trans Am project in my garage had the louvers on it when I got the car. They were immediately taken off to find, much to my surprise, that the UV rays of the sun had actually created "louver" shades in the glass!!! The glass now looks like crap. IMHO Forget the louvers. I'd rather see rear glass tinted (yuk) than with louvers.