From the factory “oops” department.
Fuel tank is too low on its support brackets, or spare tire tray is too tall.
Solution:
Make wood blocks to support the fuel tank, raise it up higher.
A line worker calls out, “Mr. Heynes, it doesn’t reach to the hole in the support bracket.”
Mr. Heynes: “Weld on an extension tab with a hole in the middle.”
“Sir, it still doesn’t fit.”
Heyes: “Drill a third hole.”
Now it fits on the middle hole.
You might want to substitute those wood blocks for some rubber ot something that is not as hard, like rubber or increase size spreads the weight to keep it from point loading.
Full gas tank and a couple of goid bumps and you’d likely have some rectangular dimples that just happen to match the wood blocks.