Good luck. We tried that on the stripe on my car when it still had its original finish. We went through to the red primer without much effort. It was just worn and faded that much.
I can't answer for '64 but on my '67, the interior has several factory colors so you may have the same.
Maybe these threads will give you some leads on how to hunt down the name and codes.
interior paint
which got me back to here
Interior color.
