I remember we ran into some confusion when we were installing a new fuel tank and lines on my '71 V code Challenger a while back. We had began to install one line incorrectly and the vapor return line didn't seem to be ending up where we expected it, until we figured out the short piece went up from the frame along the inner fender and attached to a longer section coming from the fuel tank with a piece of rubber fuel line (the fact that we were installing the lines at about 3 in the morning might have had something to do with it!)
I forget which of the companies I bought my set from, but they assured me it included all the clamps and clips I needed. What I found was missing from their line kit was the clip and bolt that installs in that indentation on the inner fender. If your car has the correct inner fender it should have the indentation with a hole for the bolt, where the clip goes. I searched around but didn't find anyone selling a reproduction of that clip and bolt. I ended up buying a used one from a Moparts member, cleaned it up and used it. I'm at work so I don't have my pictures showing that clip and bolt here to post right now.