I don't know of any visual differences between them, but if you look up the block number at mortec.com you might be able to find it. The block number is stamped into a boss on the block just forward of the passenger side head.
Are you looking for the pad that has the engine serial number and suffix code on it? That one is in front of the passenger side cylinder head. The timing pad is just above the harmonic balancer, usually on the driver's side.