Looking at the pictured bearing, it appears to be similar in design to the original, but as you say evidently does not separate.
Since it has the same dimensions as required, perhaps it's meant to be installed as a one piece unit, driven into the outer hub bearing race recess. Guessing once you drive it into place, then you'll have to hand pack the bearing with grease and it stays in the hub while sliding the hub over the spindle. I suppose you could pre-pack the bearing with grease before driving it into the hub, but you'd need to be sure and clean the outer surface of the unit before installing IMO.
I've personally not seen a bearing like this, but perhaps other Bolters have???
