Pigeon Blood is the type of discus (or mutation if you will)....marlboro red is just the commercial name for a variant of the Pigeon Blood. Either way, all Pigeon Blood based discus have varying degrees of peppering. A lot of hobbyists and breeders determine the quality of a Pigeon Blood based discus for quality not only by shape and whatnot....but also by the intensity of the peppering. The less peppering the better. There are Pigeon Blood based discus out there now that have virtually zero peppering (extremely minute "dusting" along the anal fin and near the mouth). Of course they are sold as very high quality fish.
-Ryan