If by "unique" you mean if it counts towards the set where other buildings have to touch it to provide further bonuses, then no. There have to be 4 other buildings touching the Palace to get the full bonus:
Eastern Palace Tower
Western Palace Tower
Maharajah's Jungle Pond
Bandar Playground
I got the last one I needed for the full bonus (Bandar Playground) in a daily challenge a few weeks ago.