Vintage Atlantc Worldmaster non-ETA mvt. with day/date complication ?!?!?

Hello.
I want to buy a vintage good swiss watch and I visited a auctions website, and I stumbled upon a watch that got my attention...

https://www.catawiki.com/it/l/94539...-riserva-unitas-6308n-rarissim-uomo-1960-1969

I am an Atlantic collector, this is a famous brand in the eastern Europe, but I never encountered the vintage model having also day and date complications.
The seller claims to be original, does anyone with higher knowledge if this watch is original, and highly rare, as its seller says in the watch's description? Because if it is how is said then this watch is a real pearl in a shell...
Thank you all!

Original in my opinion.
Another one here https://zegarkiclub.pl/forum/topic/133134-atlantic-worldmaster-original/

It must be “original “ it says so right on the dial. 🤣😂😂