The Devil's Passkey was Stroheim's second film as director-writer-producer for Hollywood, after his prestigious debut with the acclaimed Blind Husbands. Unfortunately, and more disastrously even than with Ambersons, all the prints of Devil's Passkey are lost, decayed in the vaults when the studio thought to check upon them decades later. That's why finding a 'lost' Shadow episode is better.
However, upon dubbing a cassette of this broadcast for Jeff, I've found that it's not the original at all, but is instead a recent performance of, I believe, the original script, presented in a nearly perfect pastiche of the original show, and featuring Mercury veteran Arthur Anderson, who appeared on the air as Jim Hawkins in Treasure Island and set off the Mercury sprinkler system during a live performance of the fascist-dress Ceasar, among other things.
So, I'm either an incurable ignoramus or an optimist, but the idea of Welles directing Stroheim, or particularly the inverse, is particulary intriguing.
Sto Pro Veritate