Try this site
http://www.internetmodeler.com/2003/...lor_part_1.htm and/or this site
http://www.cybermodeler.com/color/usn_ww2.shtml
You might be able to find a color picker to match them, or maybe you have a way to convert the FS (Federal Standard) numbers to hex equivalents.
Is there a need? That's a matter of opinion- in mine, yes! I'd love to see more authentic schemes, especially for the later war period.
Lemme know if you need anything else.