After a Hammer Brother has moved, it will always face a specific direction. This way you can tell which HB that has which item.

HB1: Facing Right
HB2: Facing Left
HB3: Facing Right

World 1: HB1 = Star
World 2: HB1 = Music Box  	HB2 = Hammer   	HB3 = Flute
World 3: HB1 = Star       	HB2 = Hammer
World 4: HB1 = P-Wing      	HB2 = Star      HB3 = Cloud
World 5: HB1 = Star        	HB2 = Music Box HB3 = P-Wing
World 6: HB1 = Hammer      	HB2 = Cloud     HB3 = Star