See that spring? It compresses the center of the seal against the crank. The outside metal ring is rigid to create friction against the case to keep it sealed and in place. Whether it is spring in or spring out, it doesn't affect the way the seal resists lateral movement and seal against the crank.
That said, one thing that can improve the seal is to use a double lipped seal. Most of the treats seals are single lip.
AVX seals in California sells this inexpensive seal. It's double lipped and high quality. I've had really good luck with them.