Armature Flip Name does not really work (Blender 2.79) I duplicated the bone then flip name, but it did not really work.
(Like the attached image below.)

The name of the bone was legUp.L.
After duplicating, the new bone's name was legUp.L.001.
Then I flipped name, and it became legUp.R.001.

Why didn't it remove .001?



Blender version:2.79
I notice that flipping names is working different now in 2.79 version.

After some testintgs now I see that it only works using  W  and selecting Symetrize. This really duplicate mirrored and flip the names.

See the image below: