For that sort of crowd, you wouldn't really cancel a major clothing faux pas by excelling in your choice of accessory.
That being said, it is also important to not look like you're trying too hard. Rolex and Omega are typically loud in the same way an "improper" suit is. They might hurt more than help, whereas Patek, Vacheron or Lange would be more impressive. Socialites who care enough about these things tend to have a certain affected air about them -- they (ostensibly, if not actually) appreciate them for fine craftsmanship rather signaling, which becomes a signal of its own. It would be an easy outsider error to assume that signal is about how expensive the watch is rather than which expensive watch it is.
Subtlety is everything. It is important not to look as though you're exerting effort to fit in. And you can afford to break from the ingroup convention if your mannerisms are otherwise "correct" and everyone in the group is aware of your status.
That being said, it is also important to not look like you're trying too hard. Rolex and Omega are typically loud in the same way an "improper" suit is. They might hurt more than help, whereas Patek, Vacheron or Lange would be more impressive. Socialites who care enough about these things tend to have a certain affected air about them -- they (ostensibly, if not actually) appreciate them for fine craftsmanship rather signaling, which becomes a signal of its own. It would be an easy outsider error to assume that signal is about how expensive the watch is rather than which expensive watch it is.
Subtlety is everything. It is important not to look as though you're exerting effort to fit in. And you can afford to break from the ingroup convention if your mannerisms are otherwise "correct" and everyone in the group is aware of your status.