Are there supposed to be one on the 3rd gens? Or is this an option on some cars?

 

it was an option, I believe

 

It was an option from 82-86. GM finally dumped it because they didn't sell many.

 

It was still on the option sheet in 92 when I ordered my Z. What a waste of money and hardware.

 

i dont know, the function of it would seem good to me.
but personally, i wouldnt pay for it (cheapy me) and i think it just makes the rear look sorta tacky

 

It may have been on the option sheet, but it wasn't available. My guess is that they didn't change the option sheet from previous years. The RPO was C25 and the last year it was available was 86, when they sold just a little over 1500 of them.

 

Is it hard to see out the back when raining? Iv never driven this car in the rain so I have no idea.

 

Not really. The back stays dry as long as you keep moving at a decent pace. If you are in stop and go traffic then it gets wet but not a big deal anyway.

 

get some rain-x for your windows
i use it atleast on the back and it seems to help let the water 'slide" off more easily.
or just take a drive on the highway, at that speed it'll all blow off no matter what