Sure looks like a corn to me! Red rat is just another name for corn snakes (which are a type of rat snake). It would be considered "normal" phase. If you decide to keep it, you should have a fecal done by a vet. Most wild caught animals have intestinal parasites which can build up to unhealthy levels in captivity.
I personally would let it go & look for a captive bred (though I am not truly opposed to field collecting & have had WC animals myself).
Pretty snake!