No, I don't think it's defective. If you pull a charger, you almost always find oily residue in the LIM. Especially in an NA motor. It is dumped into the LIM and since it has recesses..it pools.

I think it's normal oil vapor that is being pushed up. At least that's my suggestion, because that gasket does absolutely nothing that I've ever found by being under the snout, except keeping the charger flat and level on the LIM.