I know for fact the fronts are straight and the rears areoffset for the 68C.
I was trying to verify from my very limited 68B archives.
But then I remembered Bob's website has lots of pictures.
If you look at Bob's pictures you will see his confirm this for me.
Jim Wilkinson's pictures show them straight too.
http://www.modelahouse.com/cgi-bin/p...cabriolets.txt