I just noticed something else in that 2007 patent for Gage's Shadow that suggests Perilla Magilla is indeed a cultivar of Perilla frutescens:
Parentage:
Female, or seed, parent.—Solenostemon scutellarioides cultivar Felix, not patented.
Male, or pollen, parent.—Perilla frutescens cultivar Magilla, not patented.