The best way to always do it is this.... There are a lot of gens pics of most watches on the net....So the easy thing to do is to compare the gen pics with the QC pics you are sent if you're not sure exactly what to look for, but bearing in mind no rep is perfect. After you have done that mention the flaws to your TD and ask if those changes can be made and if not you should know what to do next.
Always get a good idea about the rep you're buying and the different qualities out there before you jump into buying.
QC pics are meant for you , it's you who would be wearing the watch at the end of the day and so for your own good you should do this and not rely on others. Good luck with your purchase