I've seen a red chocobo in Ozmone on a couple of occasions. It was not level 99 nor did it drop a ribbon. The only items I can recall are the basic fire magicite and chocobo feather.

=o However, the guide does have "Lv99 Red Chocobo" listed as a possible enemy in Ozmone, with a ribbon as a drop. It has 239,686 HP, though, so good luck.