Hi, I'm not sure about the 68 Bird, but on the 67 I found on "Firebirdgallery.com" that they actually tell you what color stripe came on what color car.
My HO was ordered with out the stripe and on the PHS document it says so.
I have since put the stripe on, because no one knew it was an HO.
I was against putting it on at first because it wasn't ordered with it, but I love it now.
Sandi