It would appear the the new seal SKR 17144 is a single lip seal and the Grease Seal # RG06-050 that you originally had is a double lip seal. That is the only difference that I can find on the seals. The double lip is better at keeping dirt and water out and the clean grease in.
You will have a little play between the grease seal and the inner bearing on the hub, without it the bearings could cause damage to the grease seal. Once you slide the hub onto the spindle the grease seal will... view full answer...