Well, not exactly "one" of a kind, there are three others.
Wouldn't you cause a stir if you registered over there and posted pics of my Black Lung! You'd hear the palpitations all the way to Hawaii. And then they'd ban your sorry a$$ too. HERESY!!! BURN THE WITCH!!!
I got an email from one of the other three guys, listing his lug engravings. I used the best magnification I've got and spotted similar engraved numbers but, taking a trick from the vintage Rolex playbook, my Doxa engravings are deployed on different lugs than his. Interestingly mine has engraved on the caseback "11889-4" which would seem to correspond to watch #4.
Must... buy... bigger... crowbar!! My other watches are starting to feel abandoned and are booking vacations to places where the sun is shining.