Even more rare than a COMEX must be this CNEXO. Marcello Pisany photographed and wrote about a Sea-Dweller with this inscription on the back. Click here to see it.
However, the Rolex-guys at WatchUseek think otherwise 🙂 Everyone can engrave it with their company name they say, which is true ofcourse. But this doesn’t explain why the ‘standard’ Rolex inscription ‘Original Gas Escape Valve’ is written without ‘Original’ on this picture. The standard casebacks for the Sea-Dweller are different and I can’t imagine Rolex would deliver standard Sea-Dwellers without the correct ‘standard’ inscription or without any inscription at all.
The easiest thing to do is send a picture of this watch to Rolex in Switzerland, to let them confirm if it is a custom inscription done by a jeweler or that these are factory-off.