I bought my z28 last month and I have not seen another one with a roll bar type trim piece that goes side to side .Is this original or an expensive add on

 

RK Sport used to make a decorative plastic light bar (look alike roll bar) for the 4th Gen convertibles:

Is this what you mean:



Wolfe makes a real roll bar for the convertibles:



Here's a custom NHRA certified cage for a low 8-second/168 MPH convertible:

 

Yes the rk plastic is what I have thanks