The fact that the guy refuses to give any kind of answer to the 'who were the parents' 'where did these come from' makes me suspect these guys ended with dye on them either intentional or by accident.
A gatorade soak if concentrated powder was used might do the trick. I just don't see this have ever been a genetic thing since that shade of red doesn't exist on any ball python on the belly or elsewhere. Even sunsets are more of a brown/gold.