I thought I saw one like yours on the Bay not too long ago. Absolutely beautiful watch. Currently there is one almost identical to yours (JLC) but the crown is not recessed. It is very attractive with a NOS dial replacement. Very tempted but not sure if replaced dial is a good thing.
My wife’s vintage rank has these numbers hand stamped on the case back. The deployant buckle is in pink/yellow gold, hand stamped number 22859. Movement signed Cartier and was made by Audenars Piguet. Note that dial does not have SWISS or Paris.
Take a look at this restored Platinum Tank Normale by Cartier as an example. Credit picture to watches by SJX Please come back and let us know what you found out from Cartier, it is quite a puzzle and interesting. By the way, what did the seller say about the watch?
I think Cartier has a restoration department called "Tradition". Perhaps the watch was sent there for restoration and the new dial was created with the matching hands based on their record. Perhaps the movement was not able to be restored and a new movement Cal21 was used instead? You can google Ins