I have been telling Demon owners this for years and was told several times I was wrong. One other thing to notice is the cap was taped off while installed and then removed and painted and all were crooked with the handle down a tad in the front.
Also the stripe was never in the center of the body line front to back. Also there is a top and a bottom to the stripe. Top stripe is always narrower at the door.
I installed these stripes in the 70's from mopar the fuel opening was always already cut in. There was never a left over piece for the cap