I think what you are supposed to do is get your engine nice and warm, which may take a while but you could possibly remove the front panel and drive to work--errand and then mark the needle positions before you turn off the truck.
Use a fork to remove the needles . Make the same drive, park and leave the engine running, and stick the needles back on pointing where the old ones were--- except for the fuel gauge needle.
You can now get rid of the overfull gauge by filling up the gas tank, then place the needle right above full, instead of way above full.
You will of course have to re assemble the cluster cover.
My ideas are my own. But I bet this would work.