Following the release of ISOs for Windows 10 build 15063 today, another sign points to this build being the Creators Update RTM build. The clue comes from a leaked version of the Windows 10 Update Assistant, which was recently discovered by Microsoft watcher WalkingCat (via Windows Central).
Using this tool on a PC running the Windows 10 Anniversary Update will allow you to install "the latest version of Windows 10," which is the build 15063 as seen in the screenshot below. Please note that "Creators Update" or "Windows 10 version 1703" are not mentioned anywhere though:
As you can see, this update assistant is just another way to get the Windows 10 Creators Update right away without having to join the Windows Insider program. However, it's probably better to use the latest ISOs files if you want to do a clean install on your PC.
Before proceeding, it's worth reminding that this build still has some known issues which you can check here. There is nothing major though, and we'll see if the company address them with cumulative updates in the coming days. Let us know in the comments if you successfully installed the Creators Update on your PC with this update assistant.