Hy Monsonmotors, welcome, by looking at the orientation of the seal lip on the seal in your picture, I would say it is designed to keep differential oil out of the hub. Most likely the hub bearings were supposed to be lubricated with grease when they were assembled and the seals kept the oil from washing the grease out and letting the oil contaminate the brake shoes. I know it goes against what we were taught, but if the seal lip is in good condition you could reuse it. I will spend a bit of time searching for new seals for you.