No - this is a whole new thing.

The Windows POSIX subsystem which shipped in NT 3.5.1 was a minimal implementation of POSIX syscall API plus a userland toolset. That was replaced with Interix which was renamed Services for Unix (SFU) which had a more comprehensive kernel implementation and more up to date userland. However that tech was not resurrected to build the Windows Subsystem for Linux (WSL).

Importantly, WSL doesn't ship with a distro - we download a genuine Ubuntu userland image at install-time and then run binaries within it.