I ordered new ones before I even knew what they were just because I figured on replacing all the seals while I had it apart and then discovered that the new ones were just as hard as the old ones. They were not like neoprene o-rings, but rather made of some sort of hard, fibrous material with a diagonal split so that they could expand to slip into the groove. There is probably some wear on them. Wonder when they changed the design tho? Mine had four total, two per carrier.

Mine also had a tiny seal for the oil passage where it bolts to the cylinder head. The original was a sort of filter screen/seal, but for the replacement they just sell a regular tiny o-ring that fits in the same groove without any sort of filter screen. Had to use some thick, tacky grease to hold the o-ring in place during assembly.