For some reason, North American was allowed to deliver FJ-2 and -3 Furies with a decidedly nonstandard green cockpit color. This is a picture of the cockpit of an FJ-2 in a museum that appears to be authentic.
For background, see https://tailhooktopics.blogspot.com/2015/04/cockpits.html
I haven't come across a specific specification for the color but in response to a question, have done some more research into how long North American continued to deliver FJ-2/3s with this cockpit color. Some have speculated that the changeover to a Dark Gull Gray interior occurred when FJ-3s began to be delivered in the gray/white scheme (note that the requirement for a DGG cockpit predated the one for a Light Gull Gray/White exterior by almost a year. However, color photos of FJ-3Ms clearly show that at least before overhaul and for the ejection seat headrest, the green persisted although I don't know for long in production.
Note that the FJ-3M to the left of the one pictured immediately above, same squadron, appears to have a Gull Gray ejection seat headrest.
In the following example, it appears that the coating was extended to the inside of the gear doors and the wheel wells but this may not have always been the case.