Is the Dura Race Hub Sealed HB7600?
 

Does any one know if this hub is fully slealed?

it is loose-ball

thank you, saved me a lot of frustration...

Best hubs in the world, by the way.

Yep. Unbelievably smooth. Make sure not to use petroleum degreaser on them though, as you can ruin the plastic faces.

You know, "loose ball" and "well sealed" are not mutually exclusive at all.
As to the hub in question, it's definitely loose ball and probably unsealed.

It has a plastic snap-on 'dust shield' over the bearings, which doesn't really stop anything.