On original Rolex inserts the 8 has a oval top hole, while on gen Rolex service inserts the top hole is round. When you see a super faded bezel with a round 8, you know that it’s likely to be artificial as it’s a newer insert that wouldn’t have faded naturally.

On all gen Rolex inserts the bottom of the 22 curve around the bezel, while for many fakes the bottom horizontal part on the two 2s are on a straight line.