I ordered a fuel filler neck, the rubber piece, from BJ's off-road. I have had good luck with everything else purchased for the truck from there but be aware. The fuel filler neck is about 2 inches shorter and I got maybe an inch of it into the fuel tank lip.
It's on solid but not as far as I'd like it to be. Also they aren't faithful reproductions I don't believe, they are wrapped in a rubber strip spiraled around the entire thing that increased the diameter to the point I couldn't use the grommet through the bed.
Just thought I'd put that out there, I was a little surprised when I opened the box and compared it to the original I pulled off the truck.
Hope that saves someone else a surprise!