Yeah, you're right, Tom. I guess to update the joke to suit modern American technology, jargon and the "new" demographics, the man in the trench coat should be offering photos of the guy's wife on a diskette or a zip drive. And maybe I'd have to change "trench coat" to "hoodie"? Also, who stands in city alleys anymore - and lives to tell about it? And to be 100% PC, there'd have to be a racial balance so that at least one of the main characters would have to be a minority figure, preferably with some kind of disability. And...and...and...
Oh, heck! Forget it. It's not worth the effort to bring a classic joke into the 21st Century.
It's better off staying in Grandpa's time.
Marshall