There are some but not many sellers here are "honest".
Well, I know one mall which is Blok M Plaza which you could see much of pre-owned watches vary in prices from vintage omega, corum, or vintage brands (not much though) to urwerk or Greubel Forsey. And then I could accompany you if you want to if I was free like on weekends or after working hours. There are several places that you could go to beside this Blok M plaza that have pre-owned watches for sale but so far they're only got a couple of them per mall, and mostly opens only till Saturday 7 pm compared to (I think) a dozen of them on Blok M plaza.
Well.... Welcome to Jakarta and happy hunting!
🤣
Best
Jev