Interesting tidbit!
I was looking around and found this one at Windvintage:https://www.windvintage.com/patek-philippe-reference-3941j-unpolished and this one at Philips: www.phillips.com
25.
Do you know why this one doesn't have the same subdial on the right side (I prefer yours)? So only a couple dozen were made and they also have different dials?