Top Gun is closest to Gen IMO. but for long term wear, i'd say the 3717 holds up better as the PVD coating on the TopGun tends to get scratched/smudged easily, at least in my case.
I have a Topgun (V2) and compared it with the real one at the AD's shop window. Used a polish cloth to make the pushers and crown less grey and now they look just like the real ones. Believe me besides the Top Gun logo that is not grey enough it is very hard to define it as a rep.
I think this is one of the best reps I know and I have several super reps.
Among them is the 3717 and however it is very near to the real one and has a super good AR (probably improved it since they started to produce).
there are some tells. One of them is the bracelet that seems to have the angels of the blocks more rounded. Now to the scratches. I am sure the watch is full ceramic (even passed the safety check at the airport without letting the metal detector beep). The watch is one of my daily beaters but it looks still like new. No scratches whatever and I had several incidents that would have made damages to other watches. I have worn brand watches out of a 200 euro price range and they looked beaten up after wearing it as long as this Top Gun. The strap also still looks like and I never expected it to be of such a good quality. Some time ago when the Top Gun was still being sold I read reviews on the IWC website and there several complaint the ceramic was broken. Well i dropped mine, abused it (by accident) several times but my Chinese Top Gun is still in great condition.