I own a 01. 5 and there IS NOT an extra port on the fill tube. However, I have relocated my fuel return using the original fill tube.
I just drilled a 3/8 hole in the side of the filler tube and brazed in a short piece of tubing. (It should go without saying, but remove the filler tube assembly from the truck to do the work!!!) The factory filler tube has a coating on it and weld/braze WILL NOT stick to it! Carefully grind it off around where you will braze the fitting and it will stick fine. I painted the area before putting it back on the truck to give back some of the lost anti-rust protection.
You could also cut the rubber hose between the fill tube and tank and put a fitting in there. However, I felt adding a fitting to the filler tube was neater and less likely to cause flow problems when filling the tank.
Steve Keim