Regarding your question, these hour markers have been used before in vintage Pateks, one such example being the ref 2481. (They’ve also been used in other vintage time only watches like in vintage IWC cal 89).
If you look at ref 2481, another feature it shares with your 5212 and 5004 is its stepped lugs, a less commonly seen feature which is very charming. Certainly the 2481 is a reference I enjoy wearing. And that 5212 of yours is beautiful, something I’d love to own someday!