I also wanted to present my Eterna-Matic Centenaire here after showing it in
yesterday's WRUW - here's a good place to go a bit more into detail ;-)
It's a Reference No. 765, in an 18k gold case produced by Serva SA in La Chaux-de-Fonds, with the 1438U automatic movement (21 jewels, quick-change date) that was introduced in 1959. The serial number dates it to 1962. The original Eterna bracelet is still in presentable & wearable condition, the original gold-plated buckle did suffer a bit, though. The crown is still original, too - all in all, I would think the watch has been worn a few short years, then stashed in a drawer when the original wearer replaced it with an end-of-the-1960s Omega.
The picture of the movement below is before the service.