Nomer
437
I'm no expert but...
The areas I would research are:
1. Ginebra is Spanish for Geneve. As such a good place to start is to query Patek or research their activities in Spain or Spanish speaking areas in the 60s.
2. The "swiss made" seems a bit unusual/suspicious as the common version of this label appear to be simply "swiss" on the mainstream 3537. In fact, I've not been able to find an example of "swiss made" on a Patek watch (but this was only a limited search). Also note that "swiss made" is now a specific term which began to be regulated from the early 70s. It could be the kind of quality moniker someone might want to add ex-post to a fresh watch face in the hopes of a resale - pure speculation.
3. In the typical 3537, the "swiss" label appears below the figure at six oclock not on top of it as in your example.
4. In the mainstream 3537, the label for Patek Philippe is without the "& Co" element. Perusing Patrizzii/Banberry shows that "& Co" rarely if ever shows up after the 40s/50s. I cold not find it in watches from the 60s - they simply state "Patek Philippe".
This is really just a quick analysis and I'm sure there are more experts online but these are the areas I would focus on if it were my watch.
