matco wheel question

Has the Matco nose wheel always had a spacer between the bearings or at least one of the inserts functioned as a spacer as I see on their website? I watched my wife land our rv-6a and it looked like I could see the nose gear vibrate fore and aft for about the first 50 feet or so. She felt no vibration. I discovered this on the first condition inspection and it was like that when purchased. It has used the tension on the axle bolt with a castle nut to set the preload on the bearings. I have been searching to see if this is correct but I suspect it is not.