Like if it was fighting, would Hidden Power be physical?
Don't ask me why.
Yes, Hidden Power would be physical or special depending on type: http://Pokemondb.net/pokebase/40871/gen-iii-hidden-power-type
So here are what types of Hidden Power are physical and which are special. Special: Fire, Water, Electric, Grass, Ice, Psychic, Dragon, Dark. Physical: Fighting, Poison, Ground, Flying, Bug, Rock, Ghost, Steel.