1. Droid PositionSundari Flatlands, Southwestern part, droid is flying in air, bellow the bridge.
2. Droid PositionSundari Flatlands, Western part, at the top of a big junk pile.
3. Droid PositionGorinth Canyon, North from Lifts, on a balcony that is attached to a rock.
4. Droid PositionGorinth Canyon, Northeastern Troida Military Workshop, at the top of a compound.
5. Droid PositionMarkaran Plains, Southern part, at the top of the building that comes out of a rock.
6. Droid PositionCamp Traken-4, North From Markaran Plains, at the top of the building.
Source: Official MCR-99 droid locations (hidden planetary achievements), MCR-99 Droid Locations post 2.0 on Swtor official Forums.
We would like to thank SWTOR community members for all additional information.