I have confirmed with David Leone, the author of that blog post that:
Authplay.dll will continue to be installed and used for trusted content only (i.e., for Adobe-generated content, like UI elements). So you’ll continue to see it as part of the install.
What this means is that embedded Flash content that users add to their PDF files will render with the Flash Player from the OS, not the authplay.dll component installed with Acrobat.
Please let us know if you have any additional questions.
I warmly thank you for your reply and for did investigating about the presence of the file authplay.dll about whom I was worried. Thanks a lot