Corvette rear spoiler

Does anyone have any information about rear spoilers on C4 Corvettes? Mine has a spoiler on it, and I am trying to find out if this is a factory option, or an aftermarket add-on.

I looked in the Corvette black book for that....none listed as options...only possiblity is ifit was a LIngenfelter...that had ground effects and a rear deck spoiler...maybe a greenwood...those were after market options...so my take on it is it is an aftermarket add-on unless it has greenwood or Lingenfelter badging.

Thanks. I'll take take information and try to do some more research on my own. I posted a picture of this "Vette on here but I wasn't sure if it is on showing. Thanks again. It also seems to have some kind of ground effects package or body kit on it too that I haven't seen on other Corvettes. Thanks again.

check to see if it says Greenwood or Lingenfelter anywhere.... that would tip you off...

  To see this picture go to the posters profile........

I have a similar spoiler on my 86, but not with the aggressive, over the side, drop down winglets.  My has a much shorter winglet on each end but is otherwise fairly similar.  I assumed it was a factory option, as the car has no other special body work (other than that from track trial and autocross use).

My 85 has a short spoiler on it that actually say's corvette on the winglets. I did some research and it was made by GM. in the accessory catalog in 96. hope this helps