Anyone notice the drop tanks that Z10 was carrying? They are the same colour as the Z10, which is why they are really hard to notice at first glance. But if you look at the shadow that Z10 cast on the helipad, you can see that it was carrying two stores on each wing, and if you look carefully, you can just about make out the outlines of the tanks on some of the photos.
Based on the presence of the tanks, I think that this was mostly a navigational and communications exercise to test if an army aviation Z10 could communicate with, and meet up with a navy ship a a fair distance out at sea.
I believe you are indeed correct that the inner mounts have fuel tanks on them.
But the outer mounts seem to have rocket launchers(?) mounted.