I can't remember if the '68 has pushbutton door handles or not. That would be early or late style cab, although they look exactly the same. My '64 has the earlier style. Even though they look the same, when I tried to put a 1971 tank in my 1964, it took a lot of massaging to get it to fit.

I really dislike the tank in the cab. There are many tanks that will fit in where the spare tire would go under the back of the bed. I have a 1973 C-body tank that goes in like it was built for it, but haven't installed it yet.

The only good thing about the tank in the cab is if it leaks you know it right away!

R.