I clean out and regrease every wheel bearing on my vehicles with Redline CV1 grease. Sealed bearings can be taken apart, if you know how they are put together. Some use a plastic cage that holds the seal in place, others like SKF the seal is just held in with pressure. And if it's too much trouble, just shove the grease gun tip down the ABS sensor hole and squeeze.
I was able to disassemble both sealed SKF bearings/hubs on my BMW and completely clean and regrease.