> Go produces native code (no VM)

Green threads can be managed by a runtime library or VM, so no VM doesn't mean no green threads.

> the goroutines can be multiplexed (depending on implementation) to OS level threads.

Being multiplexed onto OS level threads is normal for green threads. Goroutines are "hybrid" (M:N) rather than "user-level" (N:1) threads, but anything other than 1:1 native threading means that you need a runtime or VM managing it, and its a kind of green threads.