These "real" RD are amazing. Lots of personnality (unique) and look at that movement !! Congrats, great catch ? Do you have all the paperwork ? I think these models had the Bulletin de l'Observatoire de Besançon ?
Interesting, I did not know this was feasible. My father has a RD from that era, and not sure he has the Bulletin, I will check and my ask you further details if it is feasible !
I think these early production examples (from before Carlos Diaz bought Dubuis out of the company,) are very special watches. I'm not sure anything quite like them is being made right now, and it's always seemed to me that Richemont uses the RD name to brand its efforts in the Richard Mille/Hublot aesthetic direction, as opposed to the quirky elegance of the 1990s RD. Wear that beauty in good health!