If the bearings were sealed, they would not have the EZ-lube system.
The EZ-lube is designed to push the old grease out the front, by forcing new grease in from behind the rear bearing.
If the EZ system has no prior use, and the only grease installed, was at the factory by hand packing, it will take many pumps to fill the hubs, before the new grease starts to push to the front.
In any case, to put new grease in, you would have to see some movement of grease at the front bearing, at the gun tip, around the zerk.
Jerry