This is an example of a rallye body.
I don't think yours is but I'd need to see it ingame.
Edit: Let's put it this way: The above one is forbidden. I don't know of another 70s rallye-style body right now, but if a body isn't something you'd find on a stock, mass-produced car, it's probably forbidden. So the one from gridghost, from the picture he posted I'm 95% sure it's allowed.
That okay, @AirJordan?
(From the looks, I didn't find it in my game though. So @gridghost can you send me a PM with what base body that is?)