Zodiac Astrographic SST Automatic Vintage

I do not know much about this watch but I do know something’s it does work. I just don’t know how to set it because the little dial thing is missing that would need repaired. It scratched up a tad bit but wouldn’t take much buffing or whatever you do with it that gets scratches out. Has a small looks like weld splat see pics. Feel free to shoot me some offers. I have done some research on them. I just don’t know what or if there are any issues with it besides what I have mentioned