I missed this response sorry.
Ok a few things. The comment about the Phong case not being GEN for the rear or the CG's is completely not true. This is another one of people being full of fake knowledge. Not trying to insult anyone. This is far from the truth as it can get. EVERY Rolex looks different when it comes to cases. Why? Because it all depends on how many times its been serviced or polished. That is just one thing. The other thing is that when you order a phong case you TELL him how you want your case. If you say give me a 1680 case he will send you what ever he has. If you order one and say I want pointy crown guards or chunky grown guards or what ever, he will make it.
Get THE ROLEX SUBMARINER STORY, look at the watches. That will open your eyes. Especially the ones at the end when it comes from peoples private collection. They are all over the place with crown guards. Years ago I stopped even thinking about it. If I don't like my crown guard I shape it to how I want. But the best thing about a Phong is that you ask for what you want. I also think the picture with that phong case with the very large lugs are from when he use to use Vietnam cases. He has for the past 5 or so years, been getting cases from China. He and his son are working on a 16660 case as we speak that is fully Rolex spec. He is also possibly working on a 16710 case from my last conversation with Jensen.
While I have tons of respect for all vintage guys and I guess I am one, lol because my favorite watch is the 16610, I think it is just crazy to start talking about the profile of the back of the crown guard as a selling point on a case when if it the only problem, it can be solved with a Dremel tool and a little polish.