I can't be of great help, but there were ID bands on some of the PTO fighter aircraft in terms of large black bands on the fusealage and wings. check these pictures:
http://www.mustangsmustangs.net/p-51/p5 ... fic/10.jpg
http://www.mustangsmustangs.net/p-51/p5 ... fic/10.jpg
you can see the bands. i don't know if there were any other plans though to have the aircraft use 'dday' type ID.
as far as the coding, i'm not really sure, i could guess that there weren't as many fighter groups in the PTO as in the ETO so they could use a simple number system, which you see on a lot of the PTO planes. but this is all a guess.
wish i could be of more help, i'm sure someone here can direct you to a better answer.
brian