One of the obvious differences in the cases is the rectangular vs. round pushers. It may be the light and angles, but the lugs look different too. The 'real' Heuer (top picture) also seems to have a rolled effect where the case and crystal meet, while the 'Anniversary' model has a flat face to the case. The crowns are different also.
What's the point? I don't know - just listing obvious differences. Maybe Heuer made the case and dials look 'older' for the Anniversary edition. Both are attractive, and wouldn't be kicked out of my watch box.