It's just that some 69s did have a return line.
Look here: http://www.camaros.org/diffs69.shtml --in the chart under return fuel line.
The 69 folks outnumber we 68s and 67s. So, eventually references at least imply 69 stuff. You'll get used to it. In fact, learning the differences is very helpful.
It's great to have another 68 in the crowd!