The 1872 Sydney has, like the 1871, its own unique design. Theobverse has two distinct identifiers: the tip of Queen Victoria's nose lines up with the left hand side of the 'T' in VICTORIA, and the 'I' of DEI lines up with the crown of her head.
The reverse can be differentiated from the 1871 by the cross on top of the crown, which touches the rims.
The 1872 Sydney is about as easy to acquire as the 1871 but in top grades it gets significantly scarcer with very few pieces surviving at AU levels and above.