Tread carefully, there are a phenomenal number of fake 60's Omega Seamaster 300s out there that came from India I think. Many others have been badly replated or have horrible condition movements. I sold one last year for £250 (black/silver), price differentials between good and bad condition is 3x
If you ever get one that's not gold that you'd like to pass on please let me know, Ive been wanting a 60's one for ages