260z's were known for vapour lock with the flat top carbs on them. Hence the return line would have been important (240z's also had it however). I don't see any insulation on the fuel rail, but they did have an "asbestos based" heat shielding on them. I believe 74 260z's would have had an electric pump from factory (although it may have come later in 75). The mechanical pump was definitely phased out later on. So the electric pump may be stock? Or a later replacement?
Service manuals are floating around on the web, but there was a few versions of the flat tops used and so may not be 100% accurate depending on what you're looking at.