Yes, the wheel bearings are sealed but you can (and should) check to make sure there is grease in them. A good brand of bearings has grease, but not all of them.
Use a pick or very small screwdriver to "gently" lift the seal up. I start at the inner race. The seal will then pop out of the bearing. If you lift to hard in one spot then you will bend the seal liner. Pack the bearing full of grease and then push the seal back into place.
Then, put a good supply of grease on the inside of the dirt wiper/outer seal. It sounds like you did this part, but just wanted to repeat it for the procedure.
Lightly grease the axle and bolt everything back together.
