I was taught many years ago that the spring faces the oil you want to keep in.
Totally correct ! . the lip faces the oil being retained ( in the crankcase ) , that is how "knife edge" oil seals work that is why the lip on them is on an angel ...thats what i did in 40 years in the engineering trade anyhow
best way to fit them is if you ca find a peice of tube around the right size so you can drift them in square , use plenty of grease on the od of the seal and the id of the hole it goes into