Good catch. Here's what Google says:
"Since this initial release is a preview, you may want to download and run an additional copy of Android Studio in parallel with your current version."
Do you know what improvements this build has for android NDK? Last time I checked the Gradle build plugin for NDK was still experimental and there were a lot of hacks to build and to package native libs into apk file.
It's not the same as Eclipse, in that you could just setup a ndk build script to run when you saved a file... it's supposed to be much better (since you're supposed to edit C files and have full autocompletion and all).
The only awkward part was building the .so files - as long as you could do that (and you could always do that separately with your make files) you were good to go. Building the final apk is fine as long as you have the jni files in the right locations.
It's not in the stable channel yet, so I assume it's not really released for the broad public yet?