Use your iPhone for time, put that on your wrist and wear it.
A watch like this which was serviced should not lose much more than 30 seconds per day. So when wearing it, you’ll have a good estimate of the actual time. 😁
About losing it’s charge: just wind it every morning before strapping it on your wrist. It shouldn’t stop before the next day.
In principle, the power reserve should be in the neighborhood of 36 hours, but as long as it is keeping good time day to day, you don't need to worry too much about it.
These dials do usually have SWISS or SWISS MADE at the bottom, so it's possible that the dial was repainted at some point. We'd need better photos to determine that.
We would usually make a judgement based on the correctness and fine-ness of the printing. For example, looking at the font and the accuracy o the tick marks. Sloppy fonts and misaligned and uneven tick marks are signatures of a repainted dial
