[LMH]

Most of the grease guns I've seen in leaf spring cars are a light silver-blue metallic. No hammer type finish. I'm not sure if all Cobra's or Cobra 427's had the same color, so I'll defer that to some other input. I've seen a couple Cobra 427's using a light green-gold metallic color but I don't know if that's original or not.
As for where to find the right color, maybe search Rust Oleum paints for the color. It's very durable and works well for small stuff like this.
Larry