Yes, I do have a fuel return line. I changed the filter when I did the carb swap so I know it is new. I have no idea how old the other one was.
Fuel in to the single port on one side, fuel out on the larger port closet to center. The other port goes to fuel return, which is the smaller and closest to the edge port.
I thought about removing the line to see if gas will spew out when I crank it but I don't have extra hands so that is a dangerous proposition.