Speaking of rarity, I've been able to account for six of them now, over about 3 years of looking and researching. John Vargas was the one that started the idea of marketing the beasties with a recognizable USD logo on the dial, and I actually saw him logged onto the "other place" a couple weeks ago. I was gonna ask him if he had any more in a sock drawer someplace, but I chickened out. I mean, the man is royalty!
Some fine day, you'll get lucky like I did. In fact, there's another member of RWG that owns a Black Lung besides me. Maybe someday he'd be persuaded to part with it?