The correct part numbers are,
8641-1287Sport = Front
8641-1288Sport = Gen1 rear (long)
8641-1323Sport = Gen2 rear (short)
The Gen1 and 2 rears are interchangeable meaning Gen2s will mount on a Gen1 and vise versa. The difference being that Gen2 stock struts are shorter than Gen1s and if used as housings for Konis you need the proper length Konis to fit the housings.
Some replacement struts did end up being stighly too large to fit the Konis properly. That's why Koni included these aluminum spacer rings in rear kits. When you installed your rear Konis into the housings they either fit very snug or just a little loose. If they were loose then you used the spacer rings. I've never had a set require them so that's why I still have these.
-Chad
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