I first saw this episode in the '60's, and, being about 10, had no idea what "The Phantom of the Opera" was, it being long before Andrew Lloyd Weber's famous rendition. Even at that age, I realized that there was an underlying tragedy of Greek proportions--even the mask that "Carl" wears is Grecian in nature!
Ross Martin DOES look more...svelte in this episode. He carries off his disguises in excellent form, and without knowing the circumstances, appears in perfect health!! Too bad it didn't last. The combination of his brilliance and innovation with Robert Conrad's physical charm and strength made a magical combination.