1962 Valiant Gas Tank

Um...what? You're talking about a car over half a century old. Statistically, there are none of them left. It's not reasonable to expect to be able to walk into any ol' parts store or car dealer and pick up whatever parts you happen to want.
I realize that, but they do make new tanks for 1963 and up. So why throw out the mold to the 1960-1962?