Are both sides of a Avid rotor the same?
Rotors are identical on both sides but are marked to ensure correct rotation as they aren't bi-directional. Few hubs and forks allow for a right hand mounted disc so rotors are only marked for left hand set up. The water and mud shedding capabilities drives the design and direction they should turn.

The earlier Roadrat RB2 was designed for a right hand mounted disc brake (outwards facing on front fork) to negate pressures put on the wheel when braking. The wheel was simply reversed in the drop  out. The new RB3 fork has a left hand mounted disc brake but uses a 9mm thru-axle design which integrates with current 9mm QR hubs. Lawyer lugs achieve the same thing.