The rule of thumb is that if the rear cover on the differential can be removed, then you should look for a locking clip on the axle. If it doesn't have a rear cover, and the only way to remove the "pumpkin" is to unbolt it from the front of the axle housing, then the axles just pull out. Many times you will need a slide hammer axle remover to break the axle free. Not having taken one of these apart, I don't know what type of axle seal is used, and you should have a new seal available prior to removing the axle. Some axle bearings are sealed, and have a rubber or Viton "O" ring around the outer circumference that also needs to be replaced.