Thinking of bidding for another Ultra-Chron ref 8309 (with the rather fetching non-square date window). This watch has no Ultra-Chron logo on its back. Since it's a monocoque case, I doubt it's a case of Frankenwatch, and am wondering: were early (or later) Ultra-Chrons made without this additional decoration?

(images are not from the actual watch, but same model - one is without, the other with logo/inscription on the back).

 

Yeah, some of them seem to lack logos on the back, I think maybe the earliest ones?

E.g. : https://auctions.gardinerhoulgate.c...077/the-watch-auction-twoday-auction-lot-153/