The Slick50 sold these days is an oil additive for high mileage cars, so it might show up in QS High Mileage oil. It is not the same Slick50 formula originally introduced that had PTFE (Teflon).
However, I would not use it in a car under warranty unless really needed, because most manufacturers recommend against using separate oil additives. Additive packages that are already in an oil that is API and manufacturer certified is OK for warranty purposes.