Originally Posted by
FBinNY
I doubt it. The original balls probably came in retainers which makes life easier for bike factories.
The prior owner probably rebuilt the headset replacing the lower balls with loose either because he couldn't find the identical retainer, or because he felt that loose balls would prolong the life of the headest. He might have chosen to leave the top set as original because most heaset wear occurs at the bottom.
No, that's the original design. Loose balls in the bottom for durabiltiy, caged balls (ooohh... bad image) in the top for ease of assembly. The bearings on the top get very little stress. I learned on the third or forth try to hold the fork up while unscrewing the top cup to keep from spilling loose bearings on the floor.